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openrisc: Add optimized memset #2

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@olofk olofk commented Feb 7, 2015

This adds a hand-optimized assembler version of memset and sets
__HAVE_ARCH_MEMSET to use this version instead of the generic C
routine

Signed-off-by: Olof Kindgren olof.kindgren@gmail.com

This adds a hand-optimized assembler version of memset and sets
__HAVE_ARCH_MEMSET to use this version instead of the generic C
routine

Signed-off-by: Olof Kindgren <olof.kindgren@gmail.com>
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olofk commented Feb 7, 2015

This version fixes the comments from #1 . Only cosmetical changes

  • Changed to c-style comments
  • Indent delay slot instructions
  • Clarify some comments

stffrdhrn pushed a commit that referenced this pull request Jan 17, 2017
…s enabled

Nils Holland and Klaus Ethgen have reported unexpected OOM killer
invocations with 32b kernel starting with 4.8 kernels

	kworker/u4:5 invoked oom-killer: gfp_mask=0x2400840(GFP_NOFS|__GFP_NOFAIL), nodemask=0, order=0, oom_score_adj=0
	kworker/u4:5 cpuset=/ mems_allowed=0
	CPU: 1 PID: 2603 Comm: kworker/u4:5 Not tainted 4.9.0-gentoo #2
	[...]
	Mem-Info:
	active_anon:58685 inactive_anon:90 isolated_anon:0
	 active_file:274324 inactive_file:281962 isolated_file:0
	 unevictable:0 dirty:649 writeback:0 unstable:0
	 slab_reclaimable:40662 slab_unreclaimable:17754
	 mapped:7382 shmem:202 pagetables:351 bounce:0
	 free:206736 free_pcp:332 free_cma:0
	Node 0 active_anon:234740kB inactive_anon:360kB active_file:1097296kB inactive_file:1127848kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:29528kB dirty:2596kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 184320kB anon_thp: 808kB writeback_tmp:0kB unstable:0kB pages_scanned:0 all_unreclaimable? no
	DMA free:3952kB min:788kB low:984kB high:1180kB active_anon:0kB inactive_anon:0kB active_file:7316kB inactive_file:0kB unevictable:0kB writepending:96kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:3200kB slab_unreclaimable:1408kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
	lowmem_reserve[]: 0 813 3474 3474
	Normal free:41332kB min:41368kB low:51708kB high:62048kB active_anon:0kB inactive_anon:0kB active_file:532748kB inactive_file:44kB unevictable:0kB writepending:24kB present:897016kB managed:836248kB mlocked:0kB slab_reclaimable:159448kB slab_unreclaimable:69608kB kernel_stack:1112kB pagetables:1404kB bounce:0kB free_pcp:528kB local_pcp:340kB free_cma:0kB
	lowmem_reserve[]: 0 0 21292 21292
	HighMem free:781660kB min:512kB low:34356kB high:68200kB active_anon:234740kB inactive_anon:360kB active_file:557232kB inactive_file:1127804kB unevictable:0kB writepending:2592kB present:2725384kB managed:2725384kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:800kB local_pcp:608kB free_cma:0kB

the oom killer is clearly pre-mature because there there is still a lot
of page cache in the zone Normal which should satisfy this lowmem
request.  Further debugging has shown that the reclaim cannot make any
forward progress because the page cache is hidden in the active list
which doesn't get rotated because inactive_list_is_low is not memcg
aware.

The code simply subtracts per-zone highmem counters from the respective
memcg's lru sizes which doesn't make any sense.  We can simply end up
always seeing the resulting active and inactive counts 0 and return
false.  This issue is not limited to 32b kernels but in practice the
effect on systems without CONFIG_HIGHMEM would be much harder to notice
because we do not invoke the OOM killer for allocations requests
targeting < ZONE_NORMAL.

Fix the issue by tracking per zone lru page counts in mem_cgroup_per_node
and subtract per-memcg highmem counts when memcg is enabled.  Introduce
helper lruvec_zone_lru_size which redirects to either zone counters or
mem_cgroup_get_zone_lru_size when appropriate.

We are losing empty LRU but non-zero lru size detection introduced by
ca70723 ("mm: update_lru_size warn and reset bad lru_size") because
of the inherent zone vs. node discrepancy.

Fixes: f8d1a31 ("mm: consider whether to decivate based on eligible zones inactive ratio")
Link: http://lkml.kernel.org/r/20170104100825.3729-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Nils Holland <nholland@tisys.org>
Tested-by: Nils Holland <nholland@tisys.org>
Reported-by: Klaus Ethgen <Klaus@Ethgen.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: <stable@vger.kernel.org>	[4.8+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Feb 6, 2017
Mathieu reported that the LTTNG modules are broken as of 4.10-rc1 due to
the removal of the cpu hotplug notifiers.

Usually I don't care much about out of tree modules, but LTTNG is widely
used in distros. There are two ways to solve that:

1) Reserve a hotplug state for LTTNG

2) Add a dynamic range for the prepare states.

While #1 is the simplest solution, #2 is the proper one as we can convert
in tree users, which do not care about ordering, to the dynamic range as
well.

Add a dynamic range which allows LTTNG to request states in the prepare
stage.

Reported-and-tested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Sewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701101353010.3401@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
stffrdhrn pushed a commit that referenced this pull request Feb 6, 2017
Syzkaller fuzzer managed to trigger this:

    BUG: sleeping function called from invalid context at mm/shmem.c:852
    in_atomic(): 1, irqs_disabled(): 0, pid: 529, name: khugepaged
    3 locks held by khugepaged/529:
     #0:  (shrinker_rwsem){++++..}, at: [<ffffffff818d7ef1>] shrink_slab.part.59+0x121/0xd30 mm/vmscan.c:451
     #1:  (&type->s_umount_key#29){++++..}, at: [<ffffffff81a63630>] trylock_super+0x20/0x100 fs/super.c:392
     #2:  (&(&sbinfo->shrinklist_lock)->rlock){+.+.-.}, at: [<ffffffff818fd83e>] spin_lock include/linux/spinlock.h:302 [inline]
     #2:  (&(&sbinfo->shrinklist_lock)->rlock){+.+.-.}, at: [<ffffffff818fd83e>] shmem_unused_huge_shrink+0x28e/0x1490 mm/shmem.c:427
    CPU: 2 PID: 529 Comm: khugepaged Not tainted 4.10.0-rc5+ torvalds#201
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
    Call Trace:
       shmem_undo_range+0xb20/0x2710 mm/shmem.c:852
       shmem_truncate_range+0x27/0xa0 mm/shmem.c:939
       shmem_evict_inode+0x35f/0xca0 mm/shmem.c:1030
       evict+0x46e/0x980 fs/inode.c:553
       iput_final fs/inode.c:1515 [inline]
       iput+0x589/0xb20 fs/inode.c:1542
       shmem_unused_huge_shrink+0xbad/0x1490 mm/shmem.c:446
       shmem_unused_huge_scan+0x10c/0x170 mm/shmem.c:512
       super_cache_scan+0x376/0x450 fs/super.c:106
       do_shrink_slab mm/vmscan.c:378 [inline]
       shrink_slab.part.59+0x543/0xd30 mm/vmscan.c:481
       shrink_slab mm/vmscan.c:2592 [inline]
       shrink_node+0x2c7/0x870 mm/vmscan.c:2592
       shrink_zones mm/vmscan.c:2734 [inline]
       do_try_to_free_pages+0x369/0xc80 mm/vmscan.c:2776
       try_to_free_pages+0x3c6/0x900 mm/vmscan.c:2982
       __perform_reclaim mm/page_alloc.c:3301 [inline]
       __alloc_pages_direct_reclaim mm/page_alloc.c:3322 [inline]
       __alloc_pages_slowpath+0xa24/0x1c30 mm/page_alloc.c:3683
       __alloc_pages_nodemask+0x544/0xae0 mm/page_alloc.c:3848
       __alloc_pages include/linux/gfp.h:426 [inline]
       __alloc_pages_node include/linux/gfp.h:439 [inline]
       khugepaged_alloc_page+0xc2/0x1b0 mm/khugepaged.c:750
       collapse_huge_page+0x182/0x1fe0 mm/khugepaged.c:955
       khugepaged_scan_pmd+0xfdf/0x12a0 mm/khugepaged.c:1208
       khugepaged_scan_mm_slot mm/khugepaged.c:1727 [inline]
       khugepaged_do_scan mm/khugepaged.c:1808 [inline]
       khugepaged+0xe9b/0x1590 mm/khugepaged.c:1853
       kthread+0x326/0x3f0 kernel/kthread.c:227
       ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430

The iput() from atomic context was a bad idea: if after igrab() somebody
else calls iput() and we left with the last inode reference, our iput()
would lead to inode eviction and therefore sleeping.

This patch should fix the situation.

Link: http://lkml.kernel.org/r/20170131093141.GA15899@node.shutemov.name
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Oct 30, 2017
Guillaume Nault says:

====================
l2tp: fix some races in session deletion

L2TP provides several interfaces for deleting sessions. Using two of
them concurrently can lead to use-after-free bugs.

Patch #2 uses a flag to prevent double removal of L2TP sessions.
Patch #1 fixes a bug found in the way. Fixing this bug is also
necessary for patch #2 to handle all cases.

This issue is similar to the tunnel deletion bug being worked on by
Sabrina: https://patchwork.ozlabs.org/patch/814173/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Oct 30, 2017
The following lockdep splat has been noticed during LTP testing

  ======================================================
  WARNING: possible circular locking dependency detected
  4.13.0-rc3-next-20170807 #12 Not tainted
  ------------------------------------------------------
  a.out/4771 is trying to acquire lock:
   (cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff812b4668>] drain_all_stock.part.35+0x18/0x140

  but task is already holding lock:
   (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #3 (&mm->mmap_sem){++++++}:
         lock_acquire+0xc9/0x230
         __might_fault+0x70/0xa0
         _copy_to_user+0x23/0x70
         filldir+0xa7/0x110
         xfs_dir2_sf_getdents.isra.10+0x20c/0x2c0 [xfs]
         xfs_readdir+0x1fa/0x2c0 [xfs]
         xfs_file_readdir+0x30/0x40 [xfs]
         iterate_dir+0x17a/0x1a0
         SyS_getdents+0xb0/0x160
         entry_SYSCALL_64_fastpath+0x1f/0xbe

  -> #2 (&type->i_mutex_dir_key#3){++++++}:
         lock_acquire+0xc9/0x230
         down_read+0x51/0xb0
         lookup_slow+0xde/0x210
         walk_component+0x160/0x250
         link_path_walk+0x1a6/0x610
         path_openat+0xe4/0xd50
         do_filp_open+0x91/0x100
         file_open_name+0xf5/0x130
         filp_open+0x33/0x50
         kernel_read_file_from_path+0x39/0x80
         _request_firmware+0x39f/0x880
         request_firmware_direct+0x37/0x50
         request_microcode_fw+0x64/0xe0
         reload_store+0xf7/0x180
         dev_attr_store+0x18/0x30
         sysfs_kf_write+0x44/0x60
         kernfs_fop_write+0x113/0x1a0
         __vfs_write+0x37/0x170
         vfs_write+0xc7/0x1c0
         SyS_write+0x58/0xc0
         do_syscall_64+0x6c/0x1f0
         return_from_SYSCALL_64+0x0/0x7a

  -> #1 (microcode_mutex){+.+.+.}:
         lock_acquire+0xc9/0x230
         __mutex_lock+0x88/0x960
         mutex_lock_nested+0x1b/0x20
         microcode_init+0xbb/0x208
         do_one_initcall+0x51/0x1a9
         kernel_init_freeable+0x208/0x2a7
         kernel_init+0xe/0x104
         ret_from_fork+0x2a/0x40

  -> #0 (cpu_hotplug_lock.rw_sem){++++++}:
         __lock_acquire+0x153c/0x1550
         lock_acquire+0xc9/0x230
         cpus_read_lock+0x4b/0x90
         drain_all_stock.part.35+0x18/0x140
         try_charge+0x3ab/0x6e0
         mem_cgroup_try_charge+0x7f/0x2c0
         shmem_getpage_gfp+0x25f/0x1050
         shmem_fault+0x96/0x200
         __do_fault+0x1e/0xa0
         __handle_mm_fault+0x9c3/0xe00
         handle_mm_fault+0x16e/0x380
         __do_page_fault+0x24a/0x530
         do_page_fault+0x30/0x80
         page_fault+0x28/0x30

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock.rw_sem --> &type->i_mutex_dir_key#3 --> &mm->mmap_sem

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&mm->mmap_sem);
                                 lock(&type->i_mutex_dir_key#3);
                                 lock(&mm->mmap_sem);
    lock(cpu_hotplug_lock.rw_sem);

   *** DEADLOCK ***

  2 locks held by a.out/4771:
   #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530
   #1:  (percpu_charge_mutex){+.+...}, at: [<ffffffff812b4c97>] try_charge+0x397/0x6e0

The problem is very similar to the one fixed by commit a459eeb
("mm, page_alloc: do not depend on cpu hotplug locks inside the
allocator").  We are taking hotplug locks while we can be sitting on top
of basically arbitrary locks.  This just calls for problems.

We can get rid of {get,put}_online_cpus, fortunately.  We do not have to
be worried about races with memory hotplug because drain_local_stock,
which is called from both the WQ draining and the memory hotplug
contexts, is always operating on the local cpu stock with IRQs disabled.

The only thing to be careful about is that the target memcg doesn't
vanish while we are still in drain_all_stock so take a reference on it.

Link: http://lkml.kernel.org/r/20170913090023.28322-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Artem Savkov <asavkov@redhat.com>
Tested-by: Artem Savkov <asavkov@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Oct 30, 2017
printk_ratelimit() invokes ___ratelimit() which may invoke a normal
printk() (pr_warn() in this particular case) to warn about suppressed
output.  Given that printk_ratelimit() may be called from anywhere, that
pr_warn() is dangerous - it may end up deadlocking the system.  Fix
___ratelimit() by using deferred printk().

Sasha reported the following lockdep error:

 : Unregister pv shared memory for cpu 8
 : select_fallback_rq: 3 callbacks suppressed
 : process 8583 (trinity-c78) no longer affine to cpu8
 :
 : ======================================================
 : WARNING: possible circular locking dependency detected
 : 4.14.0-rc2-next-20170927+ torvalds#252 Not tainted
 : ------------------------------------------------------
 : migration/8/62 is trying to acquire lock:
 : (&port_lock_key){-.-.}, at: serial8250_console_write()
 :
 : but task is already holding lock:
 : (&rq->lock){-.-.}, at: sched_cpu_dying()
 :
 : which lock already depends on the new lock.
 :
 :
 : the existing dependency chain (in reverse order) is:
 :
 : -> #3 (&rq->lock){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock()
 : task_fork_fair()
 : sched_fork()
 : copy_process.part.31()
 : _do_fork()
 : kernel_thread()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> #2 (&p->pi_lock){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : try_to_wake_up()
 : default_wake_function()
 : woken_wake_function()
 : __wake_up_common()
 : __wake_up_common_lock()
 : __wake_up()
 : tty_wakeup()
 : tty_port_default_wakeup()
 : tty_port_tty_wakeup()
 : uart_write_wakeup()
 : serial8250_tx_chars()
 : serial8250_handle_irq.part.25()
 : serial8250_default_handle_irq()
 : serial8250_interrupt()
 : __handle_irq_event_percpu()
 : handle_irq_event_percpu()
 : handle_irq_event()
 : handle_level_irq()
 : handle_irq()
 : do_IRQ()
 : ret_from_intr()
 : native_safe_halt()
 : default_idle()
 : arch_cpu_idle()
 : default_idle_call()
 : do_idle()
 : cpu_startup_entry()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> #1 (&tty->write_wait){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : __wake_up_common_lock()
 : __wake_up()
 : tty_wakeup()
 : tty_port_default_wakeup()
 : tty_port_tty_wakeup()
 : uart_write_wakeup()
 : serial8250_tx_chars()
 : serial8250_handle_irq.part.25()
 : serial8250_default_handle_irq()
 : serial8250_interrupt()
 : __handle_irq_event_percpu()
 : handle_irq_event_percpu()
 : handle_irq_event()
 : handle_level_irq()
 : handle_irq()
 : do_IRQ()
 : ret_from_intr()
 : native_safe_halt()
 : default_idle()
 : arch_cpu_idle()
 : default_idle_call()
 : do_idle()
 : cpu_startup_entry()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> #0 (&port_lock_key){-.-.}:
 : check_prev_add()
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : serial8250_console_write()
 : univ8250_console_write()
 : console_unlock()
 : vprintk_emit()
 : vprintk_default()
 : vprintk_func()
 : printk()
 : ___ratelimit()
 : __printk_ratelimit()
 : select_fallback_rq()
 : sched_cpu_dying()
 : cpuhp_invoke_callback()
 : take_cpu_down()
 : multi_cpu_stop()
 : cpu_stopper_thread()
 : smpboot_thread_fn()
 : kthread()
 : ret_from_fork()
 :
 : other info that might help us debug this:
 :
 : Chain exists of:
 :   &port_lock_key --> &p->pi_lock --> &rq->lock
 :
 :  Possible unsafe locking scenario:
 :
 :        CPU0                    CPU1
 :        ----                    ----
 :   lock(&rq->lock);
 :                                lock(&p->pi_lock);
 :                                lock(&rq->lock);
 :   lock(&port_lock_key);
 :
 :  *** DEADLOCK ***
 :
 : 4 locks held by migration/8/62:
 : #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying()
 : #1: (&rq->lock){-.-.}, at: sched_cpu_dying()
 : #2: (printk_ratelimit_state.lock){....}, at: ___ratelimit()
 : #3: (console_lock){+.+.}, at: vprintk_emit()
 :
 : stack backtrace:
 : CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ torvalds#252
 : Call Trace:
 : dump_stack()
 : print_circular_bug()
 : check_prev_add()
 : ? add_lock_to_list.isra.26()
 : ? check_usage()
 : ? kvm_clock_read()
 : ? kvm_sched_clock_read()
 : ? sched_clock()
 : ? check_preemption_disabled()
 : __lock_acquire()
 : ? __lock_acquire()
 : ? add_lock_to_list.isra.26()
 : ? debug_check_no_locks_freed()
 : ? memcpy()
 : lock_acquire()
 : ? serial8250_console_write()
 : _raw_spin_lock_irqsave()
 : ? serial8250_console_write()
 : serial8250_console_write()
 : ? serial8250_start_tx()
 : ? lock_acquire()
 : ? memcpy()
 : univ8250_console_write()
 : console_unlock()
 : ? __down_trylock_console_sem()
 : vprintk_emit()
 : vprintk_default()
 : vprintk_func()
 : printk()
 : ? show_regs_print_info()
 : ? lock_acquire()
 : ___ratelimit()
 : __printk_ratelimit()
 : select_fallback_rq()
 : sched_cpu_dying()
 : ? sched_cpu_starting()
 : ? rcutree_dying_cpu()
 : ? sched_cpu_starting()
 : cpuhp_invoke_callback()
 : ? cpu_disable_common()
 : take_cpu_down()
 : ? trace_hardirqs_off_caller()
 : ? cpuhp_invoke_callback()
 : multi_cpu_stop()
 : ? __this_cpu_preempt_check()
 : ? cpu_stop_queue_work()
 : cpu_stopper_thread()
 : ? cpu_stop_create()
 : smpboot_thread_fn()
 : ? sort_range()
 : ? schedule()
 : ? __kthread_parkme()
 : kthread()
 : ? sort_range()
 : ? kthread_create_on_node()
 : ret_from_fork()
 : process 9121 (trinity-c78) no longer affine to cpu8
 : smpboot: CPU 8 is now offline

Link: http://lkml.kernel.org/r/20170928120405.18273-1-sergey.senozhatsky@gmail.com
Fixes: 6b1d174 ("ratelimit: extend to print suppressed messages on release")
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Borislav Petkov <bp@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Oct 30, 2017
Thomas reported that 'perf buildid-list' gets a SEGFAULT due to NULL
pointer deref when he ran it on a data with namespace events.  It was
because the buildid_id__mark_dso_hit_ops lacks the namespace event
handler and perf_too__fill_default() didn't set it.

  Program received signal SIGSEGV, Segmentation fault.
  0x0000000000000000 in ?? ()
  Missing separate debuginfos, use: dnf debuginfo-install audit-libs-2.7.7-1.fc25.s390x bzip2-libs-1.0.6-21.fc25.s390x elfutils-libelf-0.169-1.fc25.s390x
  +elfutils-libs-0.169-1.fc25.s390x libcap-ng-0.7.8-1.fc25.s390x numactl-libs-2.0.11-2.ibm.fc25.s390x openssl-libs-1.1.0e-1.1.ibm.fc25.s390x perl-libs-5.24.1-386.fc25.s390x
  +python-libs-2.7.13-2.fc25.s390x slang-2.3.0-7.fc25.s390x xz-libs-5.2.3-2.fc25.s390x zlib-1.2.8-10.fc25.s390x
  (gdb) where
  #0  0x0000000000000000 in ?? ()
  #1  0x00000000010fad6a in machines__deliver_event (machines=<optimized out>, machines@entry=0x2c6fd18,
      evlist=<optimized out>, event=event@entry=0x3fffdf00470, sample=0x3ffffffe880, sample@entry=0x3ffffffe888,
      tool=tool@entry=0x1312968 <build_id.mark_dso_hit_ops>, file_offset=1136) at util/session.c:1287
  #2  0x00000000010fbf4e in perf_session__deliver_event (file_offset=1136, tool=0x1312968 <build_id.mark_dso_hit_ops>,
      sample=0x3ffffffe888, event=0x3fffdf00470, session=0x2c6fc30) at util/session.c:1340
  #3  perf_session__process_event (session=0x2c6fc30, session@entry=0x0, event=event@entry=0x3fffdf00470,
      file_offset=file_offset@entry=1136) at util/session.c:1522
  #4  0x00000000010fddde in __perf_session__process_events (file_size=11880, data_size=<optimized out>,
      data_offset=<optimized out>, session=0x0) at util/session.c:1899
  #5  perf_session__process_events (session=0x0, session@entry=0x2c6fc30) at util/session.c:1953
  #6  0x000000000103b2ac in perf_session__list_build_ids (with_hits=<optimized out>, force=<optimized out>)
      at builtin-buildid-list.c:83
  #7  cmd_buildid_list (argc=<optimized out>, argv=<optimized out>) at builtin-buildid-list.c:115
  #8  0x00000000010a026c in run_builtin (p=0x1311f78 <commands+24>, argc=argc@entry=2, argv=argv@entry=0x3fffffff3c0)
      at perf.c:296
  #9  0x000000000102bc00 in handle_internal_command (argv=<optimized out>, argc=2) at perf.c:348
  #10 run_argv (argcp=<synthetic pointer>, argv=<synthetic pointer>) at perf.c:392
  #11 main (argc=<optimized out>, argv=0x3fffffff3c0) at perf.c:536
  (gdb)

Fix it by adding a stub event handler for namespace event.

Committer testing:

Further clarifying, plain using 'perf buildid-list' will not end up in a
SEGFAULT when processing a perf.data file with namespace info:

  # perf record -a --namespaces sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 2.024 MB perf.data (1058 samples) ]
  # perf buildid-list | wc -l
  38
  # perf buildid-list | head -5
  e2a171c7b905826fc8494f0711ba76ab6abbd604 /lib/modules/4.14.0-rc3+/build/vmlinux
  874840a02d8f8a31cedd605d0b8653145472ced3 /lib/modules/4.14.0-rc3+/kernel/arch/x86/kvm/kvm-intel.ko
  ea7223776730cd8a22f320040aae4d54312984bc /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/i915/i915.ko
  5961535e6732a8edb7f22b3f148bb2fa2e0be4b9 /lib/modules/4.14.0-rc3+/kernel/drivers/gpu/drm/drm.ko
  f045f54aa78cf1931cc893f78b6cbc52c72a8cb1 /usr/lib64/libc-2.25.so
  #

It is only when one asks for checking what of those entries actually had
samples, i.e. when we use either -H or --with-hits, that we will process
all the PERF_RECORD_ events, and since tools/perf/builtin-buildid-list.c
neither explicitely set a perf_tool.namespaces() callback nor the
default stub was set that we end up, when processing a
PERF_RECORD_NAMESPACE record, causing a SEGFAULT:

  # perf buildid-list -H
  Segmentation fault (core dumped)
  ^C
  #

Reported-and-Tested-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Fixes: f3b3614 ("perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info")
Link: http://lkml.kernel.org/r/20171017132900.11043-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Oct 30, 2017
When an EMAD is transmitted, a timeout work item is scheduled with a
delay of 200ms, so that another EMAD will be retried until a maximum of
five retries.

In certain situations, it's possible for the function waiting on the
EMAD to be associated with a work item that is queued on the same
workqueue (`mlxsw_core`) as the timeout work item. This results in
flushing a work item on the same workqueue.

According to commit e159489 ("workqueue: relax lockdep annotation
on flush_work()") the above may lead to a deadlock in case the workqueue
has only one worker active or if the system in under memory pressure and
the rescue worker is in use. The latter explains the very rare and
random nature of the lockdep splats we have been seeing:

[   52.730240] ============================================
[   52.736179] WARNING: possible recursive locking detected
[   52.742119] 4.14.0-rc3jiri+ #4 Not tainted
[   52.746697] --------------------------------------------
[   52.752635] kworker/1:3/599 is trying to acquire lock:
[   52.758378]  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c4fa4>] flush_work+0x3a4/0x5e0
[   52.767837]
               but task is already holding lock:
[   52.774360]  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
[   52.784495]
               other info that might help us debug this:
[   52.791794]  Possible unsafe locking scenario:
[   52.798413]        CPU0
[   52.801144]        ----
[   52.803875]   lock(mlxsw_core_driver_name);
[   52.808556]   lock(mlxsw_core_driver_name);
[   52.813236]
                *** DEADLOCK ***
[   52.819857]  May be due to missing lock nesting notation
[   52.827450] 3 locks held by kworker/1:3/599:
[   52.832221]  #0:  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
[   52.842846]  #1:  ((&(&bridge->fdb_notify.dw)->work)){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
[   52.854537]  #2:  (rtnl_mutex){+.+.}, at: [<ffffffff822ad8e7>] rtnl_lock+0x17/0x20
[   52.863021]
               stack backtrace:
[   52.867890] CPU: 1 PID: 599 Comm: kworker/1:3 Not tainted 4.14.0-rc3jiri+ #4
[   52.875773] Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016
[   52.886267] Workqueue: mlxsw_core mlxsw_sp_fdb_notify_work [mlxsw_spectrum]
[   52.894060] Call Trace:
[   52.909122]  __lock_acquire+0xf6f/0x2a10
[   53.025412]  lock_acquire+0x158/0x440
[   53.047557]  flush_work+0x3c4/0x5e0
[   53.087571]  __cancel_work_timer+0x3ca/0x5e0
[   53.177051]  cancel_delayed_work_sync+0x13/0x20
[   53.182142]  mlxsw_reg_trans_bulk_wait+0x12d/0x7a0 [mlxsw_core]
[   53.194571]  mlxsw_core_reg_access+0x586/0x990 [mlxsw_core]
[   53.225365]  mlxsw_reg_query+0x10/0x20 [mlxsw_core]
[   53.230882]  mlxsw_sp_fdb_notify_work+0x2a3/0x9d0 [mlxsw_spectrum]
[   53.237801]  process_one_work+0x8f1/0x12f0
[   53.321804]  worker_thread+0x1fd/0x10c0
[   53.435158]  kthread+0x28e/0x370
[   53.448703]  ret_from_fork+0x2a/0x40
[   53.453017] mlxsw_spectrum 0000:01:00.0: EMAD retries (2/5) (tid=bf4549b100000774)
[   53.453119] mlxsw_spectrum 0000:01:00.0: EMAD retries (5/5) (tid=bf4549b100000770)
[   53.453132] mlxsw_spectrum 0000:01:00.0: EMAD reg access failed (tid=bf4549b100000770,reg_id=200b(sfn),type=query,status=0(operation performed))
[   53.453143] mlxsw_spectrum 0000:01:00.0: Failed to get FDB notifications

Fix this by creating another workqueue for EMAD timeouts, thereby
preventing the situation of a work item trying to flush a work item
queued on the same workqueue.

Fixes: caf7297 ("mlxsw: core: Introduce support for asynchronous EMAD register access")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Jan 27, 2018
With the replacement of the pid bitmap and hashtable with an idr in
alloc_pid started occassionally failing when allocating the first pid
in a pid namespace.  Things were not completely reset resulting in
the first allocated pid getting the number 2 (not 1).  Which
further resulted in ns->proc_mnt not getting set and eventually
causing an oops in proc_flush_task.

Oops: 0000 [#1] SMP
CPU: 2 PID: 6743 Comm: trinity-c117 Not tainted 4.15.0-rc4-think+ #2
RIP: 0010:proc_flush_task+0x8e/0x1b0
RSP: 0018:ffffc9000bbffc40 EFLAGS: 00010286
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00000000fffffffb
RDX: 0000000000000000 RSI: ffffc9000bbffc50 RDI: 0000000000000000
RBP: ffffc9000bbffc63 R08: 0000000000000000 R09: 0000000000000002
R10: ffffc9000bbffb70 R11: ffffc9000bbffc64 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000003 R15: ffff8804c10d7840
FS:  00007f7cb8965700(0000) GS:ffff88050a200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000003e21ae003 CR4: 00000000001606e0
DR0: 00007fb1d6c22000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 ? release_task+0xaf/0x680
 release_task+0xd2/0x680
 ? wait_consider_task+0xb82/0xce0
 wait_consider_task+0xbe9/0xce0
 ? do_wait+0xe1/0x330
 do_wait+0x151/0x330
 kernel_wait4+0x8d/0x150
 ? task_stopped_code+0x50/0x50
 SYSC_wait4+0x95/0xa0
 ? rcu_read_lock_sched_held+0x6c/0x80
 ? syscall_trace_enter+0x2d7/0x340
 ? do_syscall_64+0x60/0x210
 do_syscall_64+0x60/0x210
 entry_SYSCALL64_slow_path+0x25/0x25
RIP: 0033:0x7f7cb82603aa
RSP: 002b:00007ffd60770bc8 EFLAGS: 00000246
 ORIG_RAX: 000000000000003d
RAX: ffffffffffffffda RBX: 00007f7cb6cd4000 RCX: 00007f7cb82603aa
RDX: 000000000000000b RSI: 00007ffd60770bd0 RDI: 0000000000007cca
RBP: 0000000000007cca R08: 00007f7cb8965700 R09: 00007ffd607c7080
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd60770bd0 R14: 00007f7cb6cd4058 R15: 00000000cccccccd
Code: c1 e2 04 44 8b 60 30 48 8b 40 38 44 8b 34 11 48 c7 c2 60 3a f5 81 44 89 e1 4c 8b 68 58 e8 4b b4 77 00 89 44 24 14 48 8d 74 24 10 <49> 8b 7d 00 e8 b9 6a f9 ff 48 85 c0 74 1a 48 89 c7 48 89 44 24
RIP: proc_flush_task+0x8e/0x1b0 RSP: ffffc9000bbffc40
CR2: 0000000000000000
---[ end trace 53d67a6481059862 ]---

Improve the quality of the implementation by resetting the place to
start allocating pids on failure to allocate the first pid.

As improving the quality of the implementation is the goal remove the now
unnecesarry disable_pid_allocations call when we fail to mount proc.

Fixes: 95846ec ("pid: replace pid bitmap implementation with IDR API")
Fixes: 8ef047a ("pid namespaces: make alloc_pid(), free_pid() and put_pid() work with struct upid")
Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
stffrdhrn pushed a commit that referenced this pull request Jan 27, 2018
In the current code, when creating a new fib6 table, tb6_root.leaf gets
initialized to net->ipv6.ip6_null_entry.
If a default route is being added with rt->rt6i_metric = 0xffffffff,
fib6_add() will add this route after net->ipv6.ip6_null_entry. As
null_entry is shared, it could cause problem.

In order to fix it, set fn->leaf to NULL before calling
fib6_add_rt2node() when trying to add the first default route.
And reset fn->leaf to null_entry when adding fails or when deleting the
last default route.

syzkaller reported the following issue which is fixed by this commit:

WARNING: suspicious RCU usage
4.15.0-rc5+ torvalds#171 Not tainted
-----------------------------
net/ipv6/ip6_fib.c:1702 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
4 locks held by swapper/0/0:
 #0:  ((&net->ipv6.ip6_fib_timer)){+.-.}, at: [<00000000d43f631b>] lockdep_copy_map include/linux/lockdep.h:178 [inline]
 #0:  ((&net->ipv6.ip6_fib_timer)){+.-.}, at: [<00000000d43f631b>] call_timer_fn+0x1c6/0x820 kernel/time/timer.c:1310
 #1:  (&(&net->ipv6.fib6_gc_lock)->rlock){+.-.}, at: [<000000002ff9d65c>] spin_lock_bh include/linux/spinlock.h:315 [inline]
 #1:  (&(&net->ipv6.fib6_gc_lock)->rlock){+.-.}, at: [<000000002ff9d65c>] fib6_run_gc+0x9d/0x3c0 net/ipv6/ip6_fib.c:2007
 #2:  (rcu_read_lock){....}, at: [<0000000091db762d>] __fib6_clean_all+0x0/0x3a0 net/ipv6/ip6_fib.c:1560
 #3:  (&(&tb->tb6_lock)->rlock){+.-.}, at: [<000000009e503581>] spin_lock_bh include/linux/spinlock.h:315 [inline]
 #3:  (&(&tb->tb6_lock)->rlock){+.-.}, at: [<000000009e503581>] __fib6_clean_all+0x1d0/0x3a0 net/ipv6/ip6_fib.c:1948

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc5+ torvalds#171
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 lockdep_rcu_suspicious+0x123/0x170 kernel/locking/lockdep.c:4585
 fib6_del+0xcaa/0x11b0 net/ipv6/ip6_fib.c:1701
 fib6_clean_node+0x3aa/0x4f0 net/ipv6/ip6_fib.c:1892
 fib6_walk_continue+0x46c/0x8a0 net/ipv6/ip6_fib.c:1815
 fib6_walk+0x91/0xf0 net/ipv6/ip6_fib.c:1863
 fib6_clean_tree+0x1e6/0x340 net/ipv6/ip6_fib.c:1933
 __fib6_clean_all+0x1f4/0x3a0 net/ipv6/ip6_fib.c:1949
 fib6_clean_all net/ipv6/ip6_fib.c:1960 [inline]
 fib6_run_gc+0x16b/0x3c0 net/ipv6/ip6_fib.c:2016
 fib6_gc_timer_cb+0x20/0x30 net/ipv6/ip6_fib.c:2033
 call_timer_fn+0x228/0x820 kernel/time/timer.c:1320
 expire_timers kernel/time/timer.c:1357 [inline]
 __run_timers+0x7ee/0xb70 kernel/time/timer.c:1660
 run_timer_softirq+0x4c/0xb0 kernel/time/timer.c:1686
 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285
 invoke_softirq kernel/softirq.c:365 [inline]
 irq_exit+0x1cc/0x200 kernel/softirq.c:405
 exiting_irq arch/x86/include/asm/apic.h:540 [inline]
 smp_apic_timer_interrupt+0x16b/0x700 arch/x86/kernel/apic/apic.c:1052
 apic_timer_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:904
 </IRQ>

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 66f5d6c ("ipv6: replace rwlock with rcu and spinlock in fib6_table")
Signed-off-by: Wei Wang <weiwan@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Jul 31, 2018
…sfers

This bug happens only when the UDC needs to sleep during usb_ep_dequeue,
as is the case for (at least) dwc3.

[  382.200896] BUG: scheduling while atomic: screen/1808/0x00000100
[  382.207124] 4 locks held by screen/1808:
[  382.211266]  #0:  (rcu_callback){....}, at: [<c10b4ff0>] rcu_process_callbacks+0x260/0x440
[  382.219949]  #1:  (rcu_read_lock_sched){....}, at: [<c1358ba0>] percpu_ref_switch_to_atomic_rcu+0xb0/0x130
[  382.230034]  #2:  (&(&ctx->ctx_lock)->rlock){....}, at: [<c11f0c73>] free_ioctx_users+0x23/0xd0
[  382.230096]  #3:  (&(&ffs->eps_lock)->rlock){....}, at: [<f81e7710>] ffs_aio_cancel+0x20/0x60 [usb_f_fs]
[  382.230160] Modules linked in: usb_f_fs libcomposite configfs bnep btsdio bluetooth ecdh_generic brcmfmac brcmutil intel_powerclamp coretemp dwc3 kvm_intel ulpi udc_core kvm irqbypass crc32_pclmul crc32c_intel pcbc dwc3_pci aesni_intel aes_i586 crypto_simd cryptd ehci_pci ehci_hcd gpio_keys usbcore basincove_gpadc industrialio usb_common
[  382.230407] CPU: 1 PID: 1808 Comm: screen Not tainted 4.14.0-edison+ torvalds#117
[  382.230416] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
[  382.230425] Call Trace:
[  382.230438]  <SOFTIRQ>
[  382.230466]  dump_stack+0x47/0x62
[  382.230498]  __schedule_bug+0x61/0x80
[  382.230522]  __schedule+0x43/0x7a0
[  382.230587]  schedule+0x5f/0x70
[  382.230625]  dwc3_gadget_ep_dequeue+0x14c/0x270 [dwc3]
[  382.230669]  ? do_wait_intr_irq+0x70/0x70
[  382.230724]  usb_ep_dequeue+0x19/0x90 [udc_core]
[  382.230770]  ffs_aio_cancel+0x37/0x60 [usb_f_fs]
[  382.230798]  kiocb_cancel+0x31/0x40
[  382.230822]  free_ioctx_users+0x4d/0xd0
[  382.230858]  percpu_ref_switch_to_atomic_rcu+0x10a/0x130
[  382.230881]  ? percpu_ref_exit+0x40/0x40
[  382.230904]  rcu_process_callbacks+0x2b3/0x440
[  382.230965]  __do_softirq+0xf8/0x26b
[  382.231011]  ? __softirqentry_text_start+0x8/0x8
[  382.231033]  do_softirq_own_stack+0x22/0x30
[  382.231042]  </SOFTIRQ>
[  382.231071]  irq_exit+0x45/0xc0
[  382.231089]  smp_apic_timer_interrupt+0x13c/0x150
[  382.231118]  apic_timer_interrupt+0x35/0x3c
[  382.231132] EIP: __copy_user_ll+0xe2/0xf0
[  382.231142] EFLAGS: 00210293 CPU: 1
[  382.231154] EAX: bfd4508c EBX: 00000004 ECX: 00000003 EDX: f3d8fe50
[  382.231165] ESI: f3d8fe51 EDI: bfd4508d EBP: f3d8fe14 ESP: f3d8fe08
[  382.231176]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[  382.231265]  core_sys_select+0x25f/0x320
[  382.231346]  ? __wake_up_common_lock+0x62/0x80
[  382.231399]  ? tty_ldisc_deref+0x13/0x20
[  382.231438]  ? ldsem_up_read+0x1b/0x40
[  382.231459]  ? tty_ldisc_deref+0x13/0x20
[  382.231479]  ? tty_write+0x29f/0x2e0
[  382.231514]  ? n_tty_ioctl+0xe0/0xe0
[  382.231541]  ? tty_write_unlock+0x30/0x30
[  382.231566]  ? __vfs_write+0x22/0x110
[  382.231604]  ? security_file_permission+0x2f/0xd0
[  382.231635]  ? rw_verify_area+0xac/0x120
[  382.231677]  ? vfs_write+0x103/0x180
[  382.231711]  SyS_select+0x87/0xc0
[  382.231739]  ? SyS_write+0x42/0x90
[  382.231781]  do_fast_syscall_32+0xd6/0x1a0
[  382.231836]  entry_SYSENTER_32+0x47/0x71
[  382.231848] EIP: 0xb7f75b05
[  382.231857] EFLAGS: 00000246 CPU: 1
[  382.231868] EAX: ffffffda EBX: 00000400 ECX: bfd4508c EDX: bfd4510c
[  382.231878] ESI: 00000000 EDI: 00000000 EBP: 00000000 ESP: bfd45020
[  382.231889]  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b
[  382.232281] softirq: huh, entered softirq 9 RCU c10b4d90 with preempt_count 00000100, exited with 00000000?

Tested-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
stffrdhrn pushed a commit that referenced this pull request Jul 31, 2018
This patch avoids that lockdep reports the following:

======================================================
WARNING: possible circular locking dependency detected
4.18.0-rc1 torvalds#62 Not tainted
------------------------------------------------------
kswapd0/84 is trying to acquire lock:
00000000c313516d (&xfs_nondir_ilock_class){++++}, at: xfs_free_eofblocks+0xa2/0x1e0

but task is already holding lock:
00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (fs_reclaim){+.+.}:
  kmem_cache_alloc+0x2c/0x2b0
  radix_tree_node_alloc.constprop.19+0x3d/0xc0
  __radix_tree_create+0x161/0x1c0
  __radix_tree_insert+0x45/0x210
  dmz_map+0x245/0x2d0 [dm_zoned]
  __map_bio+0x40/0x260
  __split_and_process_non_flush+0x116/0x220
  __split_and_process_bio+0x81/0x180
  __dm_make_request.isra.32+0x5a/0x100
  generic_make_request+0x36e/0x690
  submit_bio+0x6c/0x140
  mpage_readpages+0x19e/0x1f0
  read_pages+0x6d/0x1b0
  __do_page_cache_readahead+0x21b/0x2d0
  force_page_cache_readahead+0xc4/0x100
  generic_file_read_iter+0x7c6/0xd20
  __vfs_read+0x102/0x180
  vfs_read+0x9b/0x140
  ksys_read+0x55/0xc0
  do_syscall_64+0x5a/0x1f0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #1 (&dmz->chunk_lock){+.+.}:
  dmz_map+0x133/0x2d0 [dm_zoned]
  __map_bio+0x40/0x260
  __split_and_process_non_flush+0x116/0x220
  __split_and_process_bio+0x81/0x180
  __dm_make_request.isra.32+0x5a/0x100
  generic_make_request+0x36e/0x690
  submit_bio+0x6c/0x140
  _xfs_buf_ioapply+0x31c/0x590
  xfs_buf_submit_wait+0x73/0x520
  xfs_buf_read_map+0x134/0x2f0
  xfs_trans_read_buf_map+0xc3/0x580
  xfs_read_agf+0xa5/0x1e0
  xfs_alloc_read_agf+0x59/0x2b0
  xfs_alloc_pagf_init+0x27/0x60
  xfs_bmap_longest_free_extent+0x43/0xb0
  xfs_bmap_btalloc_nullfb+0x7f/0xf0
  xfs_bmap_btalloc+0x428/0x7c0
  xfs_bmapi_write+0x598/0xcc0
  xfs_iomap_write_allocate+0x15a/0x330
  xfs_map_blocks+0x1cf/0x3f0
  xfs_do_writepage+0x15f/0x7b0
  write_cache_pages+0x1ca/0x540
  xfs_vm_writepages+0x65/0xa0
  do_writepages+0x48/0xf0
  __writeback_single_inode+0x58/0x730
  writeback_sb_inodes+0x249/0x5c0
  wb_writeback+0x11e/0x550
  wb_workfn+0xa3/0x670
  process_one_work+0x228/0x670
  worker_thread+0x3c/0x390
  kthread+0x11c/0x140
  ret_from_fork+0x3a/0x50

-> #0 (&xfs_nondir_ilock_class){++++}:
  down_read_nested+0x43/0x70
  xfs_free_eofblocks+0xa2/0x1e0
  xfs_fs_destroy_inode+0xac/0x270
  dispose_list+0x51/0x80
  prune_icache_sb+0x52/0x70
  super_cache_scan+0x127/0x1a0
  shrink_slab.part.47+0x1bd/0x590
  shrink_node+0x3b5/0x470
  balance_pgdat+0x158/0x3b0
  kswapd+0x1ba/0x600
  kthread+0x11c/0x140
  ret_from_fork+0x3a/0x50

other info that might help us debug this:

Chain exists of:
  &xfs_nondir_ilock_class --> &dmz->chunk_lock --> fs_reclaim

Possible unsafe locking scenario:

     CPU0                    CPU1
     ----                    ----
lock(fs_reclaim);
                             lock(&dmz->chunk_lock);
                             lock(fs_reclaim);
lock(&xfs_nondir_ilock_class);

*** DEADLOCK ***

3 locks held by kswapd0/84:
 #0: 00000000591c83ae (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
 #1: 000000000f8208f5 (shrinker_rwsem){++++}, at: shrink_slab.part.47+0x3f/0x590
 #2: 00000000cacefa54 (&type->s_umount_key#43){.+.+}, at: trylock_super+0x16/0x50

stack backtrace:
CPU: 7 PID: 84 Comm: kswapd0 Not tainted 4.18.0-rc1 torvalds#62
Hardware name: Supermicro Super Server/X10SRL-F, BIOS 2.0 12/17/2015
Call Trace:
 dump_stack+0x85/0xcb
 print_circular_bug.isra.36+0x1ce/0x1db
 __lock_acquire+0x124e/0x1310
 lock_acquire+0x9f/0x1f0
 down_read_nested+0x43/0x70
 xfs_free_eofblocks+0xa2/0x1e0
 xfs_fs_destroy_inode+0xac/0x270
 dispose_list+0x51/0x80
 prune_icache_sb+0x52/0x70
 super_cache_scan+0x127/0x1a0
 shrink_slab.part.47+0x1bd/0x590
 shrink_node+0x3b5/0x470
 balance_pgdat+0x158/0x3b0
 kswapd+0x1ba/0x600
 kthread+0x11c/0x140
 ret_from_fork+0x3a/0x50

Reported-by: Masato Suzuki <masato.suzuki@wdc.com>
Fixes: 4218a95 ("dm zoned: use GFP_NOIO in I/O path")
Cc: <stable@vger.kernel.org>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Jul 31, 2018
This module exposes two USB configurations: a QMI+AT capable setup on
USB config #1 and a MBIM capable setup on USB config #2.

By default the kernel will choose the MBIM capable configuration as
long as the cdc_mbim driver is available. This patch adds support for
the QMI port in the secondary configuration.

Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Jul 31, 2018
This patch avoids that removing a path controlled by the dm-mpath driver
while mkfs is running triggers the following kernel bug:

    kernel BUG at block/blk-core.c:3347!
    invalid opcode: 0000 [#1] PREEMPT SMP KASAN
    CPU: 20 PID: 24369 Comm: mkfs.ext4 Not tainted 4.18.0-rc1-dbg+ #2
    RIP: 0010:blk_end_request_all+0x68/0x70
    Call Trace:
     <IRQ>
     dm_softirq_done+0x326/0x3d0 [dm_mod]
     blk_done_softirq+0x19b/0x1e0
     __do_softirq+0x128/0x60d
     irq_exit+0x100/0x110
     smp_call_function_single_interrupt+0x90/0x330
     call_function_single_interrupt+0xf/0x20
     </IRQ>

Fixes: f9d03f9 ("block: improve handling of the magic discard payload")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
stffrdhrn pushed a commit that referenced this pull request Jul 31, 2018
A "small" CIFS buffer is not big enough in general to hold a
setacl request for SMB2, and we end up overflowing the buffer in
send_set_info(). For instance:

 # mount.cifs //127.0.0.1/test /mnt/test -o username=test,password=test,nounix,cifsacl
 # touch /mnt/test/acltest
 # getcifsacl /mnt/test/acltest
 REVISION:0x1
 CONTROL:0x9004
 OWNER:S-1-5-21-2926364953-924364008-418108241-1000
 GROUP:S-1-22-2-1001
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-1-0:ALLOWED/0x0/R
 # setcifsacl -a "ACL:S-1-22-2-1004:ALLOWED/0x0/R" /mnt/test/acltest

this setacl will cause the following KASAN splat:

[  330.777927] BUG: KASAN: slab-out-of-bounds in send_set_info+0x4dd/0xc20 [cifs]
[  330.779696] Write of size 696 at addr ffff88010d5e2860 by task setcifsacl/1012

[  330.781882] CPU: 1 PID: 1012 Comm: setcifsacl Not tainted 4.18.0-rc2+ #2
[  330.783140] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  330.784395] Call Trace:
[  330.784789]  dump_stack+0xc2/0x16b
[  330.786777]  print_address_description+0x6a/0x270
[  330.787520]  kasan_report+0x258/0x380
[  330.788845]  memcpy+0x34/0x50
[  330.789369]  send_set_info+0x4dd/0xc20 [cifs]
[  330.799511]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.801395]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.830888]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.840367]  __vfs_setxattr+0x84/0xb0
[  330.842060]  __vfs_setxattr_noperm+0xe6/0x370
[  330.843848]  vfs_setxattr+0xc2/0xd0
[  330.845519]  setxattr+0x258/0x320
[  330.859211]  path_setxattr+0x15b/0x1b0
[  330.864392]  __x64_sys_setxattr+0xc0/0x160
[  330.866133]  do_syscall_64+0x14e/0x4b0
[  330.876631]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  330.878503] RIP: 0033:0x7ff2e507db0a
[  330.880151] Code: 48 8b 0d 89 93 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 bc 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 56 93 2c 00 f7 d8 64 89 01 48
[  330.885358] RSP: 002b:00007ffdc4903c18 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
[  330.887733] RAX: ffffffffffffffda RBX: 000055d1170de140 RCX: 00007ff2e507db0a
[  330.890067] RDX: 000055d1170de7d0 RSI: 000055d115b39184 RDI: 00007ffdc4904818
[  330.892410] RBP: 0000000000000001 R08: 0000000000000000 R09: 000055d1170de7e4
[  330.894785] R10: 00000000000002b8 R11: 0000000000000246 R12: 0000000000000007
[  330.897148] R13: 000055d1170de0c0 R14: 0000000000000008 R15: 000055d1170de550

[  330.901057] Allocated by task 1012:
[  330.902888]  kasan_kmalloc+0xa0/0xd0
[  330.904714]  kmem_cache_alloc+0xc8/0x1d0
[  330.906615]  mempool_alloc+0x11e/0x380
[  330.908496]  cifs_small_buf_get+0x35/0x60 [cifs]
[  330.910510]  smb2_plain_req_init+0x4a/0xd60 [cifs]
[  330.912551]  send_set_info+0x198/0xc20 [cifs]
[  330.914535]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.916465]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.918453]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.920426]  __vfs_setxattr+0x84/0xb0
[  330.922284]  __vfs_setxattr_noperm+0xe6/0x370
[  330.924213]  vfs_setxattr+0xc2/0xd0
[  330.926008]  setxattr+0x258/0x320
[  330.927762]  path_setxattr+0x15b/0x1b0
[  330.929592]  __x64_sys_setxattr+0xc0/0x160
[  330.931459]  do_syscall_64+0x14e/0x4b0
[  330.933314]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  330.936843] Freed by task 0:
[  330.938588] (stack is not available)

[  330.941886] The buggy address belongs to the object at ffff88010d5e2800
 which belongs to the cache cifs_small_rq of size 448
[  330.946362] The buggy address is located 96 bytes inside of
 448-byte region [ffff88010d5e2800, ffff88010d5e29c0)
[  330.950722] The buggy address belongs to the page:
[  330.952789] page:ffffea0004357880 count:1 mapcount:0 mapping:ffff880108fdca80 index:0x0 compound_mapcount: 0
[  330.955665] flags: 0x17ffffc0008100(slab|head)
[  330.957760] raw: 0017ffffc0008100 dead000000000100 dead000000000200 ffff880108fdca80
[  330.960356] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
[  330.963005] page dumped because: kasan: bad access detected

[  330.967039] Memory state around the buggy address:
[  330.969255]  ffff88010d5e2880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.971833]  ffff88010d5e2900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.974397] >ffff88010d5e2980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
[  330.976956]                                            ^
[  330.979226]  ffff88010d5e2a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.981755]  ffff88010d5e2a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.984225] ==================================================================

Fix this by allocating a regular CIFS buffer in
smb2_plain_req_init() if the request command is SMB2_SET_INFO.

Reported-by: Jianhong Yin <jiyin@redhat.com>
Fixes: 366ed84 ("cifs: Use smb 2 - 3 and cifsacl mount options setacl function")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-and-tested-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Commit abbbdf1 ("replace kill_bdev() with __invalidate_device()")
once did this, but 29eaadc ("nbd: stop using the bdev everywhere")
resurrected kill_bdev() and it has been there since then. So buffer_head
mappings still get killed on a server disconnection, and we can still
hit the BUG_ON on a filesystem on the top of the nbd device.

  EXT4-fs (nbd0): mounted filesystem with ordered data mode. Opts: (null)
  block nbd0: Receive control failed (result -32)
  block nbd0: shutting down sockets
  print_req_error: I/O error, dev nbd0, sector 66264 flags 3000
  EXT4-fs warning (device nbd0): htree_dirblock_to_tree:979: inode #2: lblock 0: comm ls: error -5 reading directory block
  print_req_error: I/O error, dev nbd0, sector 2264 flags 3000
  EXT4-fs error (device nbd0): __ext4_get_inode_loc:4690: inode #2: block 283: comm ls: unable to read itable block
  EXT4-fs error (device nbd0) in ext4_reserve_inode_write:5894: IO failure
  ------------[ cut here ]------------
  kernel BUG at fs/buffer.c:3057!
  invalid opcode: 0000 [#1] SMP PTI
  CPU: 7 PID: 40045 Comm: jbd2/nbd0-8 Not tainted 5.1.0-rc3+ #4
  Hardware name: Amazon EC2 m5.12xlarge/, BIOS 1.0 10/16/2017
  RIP: 0010:submit_bh_wbc+0x18b/0x190
  ...
  Call Trace:
   jbd2_write_superblock+0xf1/0x230 [jbd2]
   ? account_entity_enqueue+0xc5/0xf0
   jbd2_journal_update_sb_log_tail+0x94/0xe0 [jbd2]
   jbd2_journal_commit_transaction+0x12f/0x1d20 [jbd2]
   ? __switch_to_asm+0x40/0x70
   ...
   ? lock_timer_base+0x67/0x80
   kjournald2+0x121/0x360 [jbd2]
   ? remove_wait_queue+0x60/0x60
   kthread+0xf8/0x130
   ? commit_timeout+0x10/0x10 [jbd2]
   ? kthread_bind+0x10/0x10
   ret_from_fork+0x35/0x40

With __invalidate_device(), I no longer hit the BUG_ON with sync or
unmount on the disconnected device.

Fixes: 29eaadc ("nbd: stop using the bdev everywhere")
Cc: linux-block@vger.kernel.org
Cc: Ratna Manoj Bolla <manoj.br@gmail.com>
Cc: nbd@other.debian.org
Cc: stable@vger.kernel.org
Cc: David Woodhouse <dwmw@amazon.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Munehisa Kamata <kamatam@amazon.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Ido Schimmel says:

====================
mlxsw: Two small fixes

Patch #1 from Jiri fixes the error path of the module initialization
function. Found during manual code inspection.

Patch #2 from Petr further reduces the default shared buffer pool sizes
in order to work around a problem that was originally described in
commit e891ce1 ("mlxsw: spectrum_buffers: Reduce pool size on
Spectrum-2").
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
lockdep reports:

   WARNING: possible circular locking dependency detected

   modprobe/302 is trying to acquire lock:
   0000000007c8919c ((wq_completion)ib_cm){+.+.}, at: flush_workqueue+0xdf/0x990

   but task is already holding lock:
   000000002d3d2ca9 (&device->client_data_rwsem){++++}, at: remove_client_context+0x79/0xd0 [ib_core]

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> #2 (&device->client_data_rwsem){++++}:
          down_read+0x3f/0x160
          ib_get_net_dev_by_params+0xd5/0x200 [ib_core]
          cma_ib_req_handler+0x5f6/0x2090 [rdma_cm]
          cm_process_work+0x29/0x110 [ib_cm]
          cm_req_handler+0x10f5/0x1c00 [ib_cm]
          cm_work_handler+0x54c/0x311d [ib_cm]
          process_one_work+0x4aa/0xa30
          worker_thread+0x62/0x5b0
          kthread+0x1ca/0x1f0
          ret_from_fork+0x24/0x30

   -> #1 ((work_completion)(&(&work->work)->work)){+.+.}:
          process_one_work+0x45f/0xa30
          worker_thread+0x62/0x5b0
          kthread+0x1ca/0x1f0
          ret_from_fork+0x24/0x30

   -> #0 ((wq_completion)ib_cm){+.+.}:
          lock_acquire+0xc8/0x1d0
          flush_workqueue+0x102/0x990
          cm_remove_one+0x30e/0x3c0 [ib_cm]
          remove_client_context+0x94/0xd0 [ib_core]
          disable_device+0x10a/0x1f0 [ib_core]
          __ib_unregister_device+0x5a/0xe0 [ib_core]
          ib_unregister_device+0x21/0x30 [ib_core]
          mlx5_ib_stage_ib_reg_cleanup+0x9/0x10 [mlx5_ib]
          __mlx5_ib_remove+0x3d/0x70 [mlx5_ib]
          mlx5_ib_remove+0x12e/0x140 [mlx5_ib]
          mlx5_remove_device+0x144/0x150 [mlx5_core]
          mlx5_unregister_interface+0x3f/0xf0 [mlx5_core]
          mlx5_ib_cleanup+0x10/0x3a [mlx5_ib]
          __x64_sys_delete_module+0x227/0x350
          do_syscall_64+0xc3/0x6a4
          entry_SYSCALL_64_after_hwframe+0x49/0xbe

Which is due to the read side of the client_data_rwsem being obtained
recursively through a work queue flush during cm client removal.

The lock is being held across the remove in remove_client_context() so
that the function is a fence, once it returns the client is removed. This
is required so that the two callers do not proceed with destruction until
the client completes removal.

Instead of using client_data_rwsem use the existing device unregistration
refcount and add a similar client unregistration (client->uses) refcount.

This will fence the two unregistration paths without holding any locks.

Cc: <stable@vger.kernel.org>
Fixes: 921eab1 ("RDMA/devices: Re-organize device.c locking")
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Link: https://lore.kernel.org/r/20190731081841.32345-2-leon@kernel.org
Signed-off-by: Doug Ledford <dledford@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
msi.c is not a module on its own right and should not have the
MODULE_[LICENSE|VERSION|AUTHOR|DESCRIPTION] definitions.

This caused a regression noticed by lkp with the following back
trace:

   WARNING: CPU: 0 PID: 1 at kernel/params.c:861 param_sysfs_init+0xb1/0x20a
   Modules linked in:
   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc1-00018-g26b3a37b928457 #2
   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
   RIP: 0010:param_sysfs_init+0xb1/0x20a
   Code: 24 38 e8 ec 17 2e fd 49 8b 7c 24 38 e8 76 fe ff ff 48 85 c0 48 89 c5 74 25 31 d2 4c 89 e6 48 89 c7 e8 6d 6f 3c fd 85 c0 74 02 <0f> 0b 48 89 ef 31 f6 e8 5d 70 a7 fe 48 89 ef e8 95 52 a7 fe 48 83
   RSP: 0000:ffff88806b0ffe30 EFLAGS: 00010282
   RAX: 00000000ffffffef RBX: ffffffff83774220 RCX: ffff88806a85e880
   RDX: 00000000ffffffef RSI: ffff88806b000400 RDI: ffff88806a8608c0
   RBP: ffff88806b392000 R08: ffffed100d61ff59 R09: ffffed100d61ff59
   R10: 0000000000000001 R11: ffffed100d61ff58 R12: ffffffff83974bc0
   R13: 0000000000000004 R14: 0000000000000028 R15: 00000000000003b9
   FS:  0000000000000000(0000) GS:ffff88806b800000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 0000000000000000 CR3: 000000000380e000 CR4: 00000000000406b0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   Call Trace:
    ? file_caps_disable+0x10/0x10
    ? locate_module_kobject+0xf2/0xf2
    do_one_initcall+0x47/0x1f0
    kernel_init_freeable+0x1b1/0x243
    ? rest_init+0xd0/0xd0
    kernel_init+0xa/0x130
    ? calculate_sigpending+0x63/0x80
    ? rest_init+0xd0/0xd0
    ret_from_fork+0x1f/0x30
   ---[ end trace 78201497ae74cc91 ]---

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 26b3a37 ("NTB: Introduce MSI library")
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
A deadlock with this stacktrace was observed.

The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio
shrinker and the shrinker depends on I/O completion in the dm-bufio
subsystem.

In order to fix the deadlock (and other similar ones), we set the flag
PF_MEMALLOC_NOIO at loop thread entry.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

  PID: 14127  TASK: ffff881455749c00  CPU: 11  COMMAND: "loop1"
   #0 [ffff88272f5af228] __schedule at ffffffff8173f405
   #1 [ffff88272f5af280] schedule at ffffffff8173fa27
   #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e
   #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5
   #4 [ffff88272f5af330] mutex_lock at ffffffff81742133
   #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio]
   #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd
   #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778
   #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34
   #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8
  #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3
  #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71
  #12 [ffff88272f5af760] new_slab at ffffffff811f4523
  #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5
  #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b
  torvalds#15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3
  torvalds#16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3
  torvalds#17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs]
  torvalds#18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994
  torvalds#19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs]
  torvalds#20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop]
  torvalds#21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop]
  torvalds#22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c
  torvalds#23 [ffff88272f5afec0] kthread at ffffffff810a8428
  torvalds#24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
…nux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm fixes for 5.3, take #2

- Fix our system register reset so that we stop writing
  non-sensical values to them, and track which registers
  get reset instead.
- Sync VMCR back from the GIC on WFI so that KVM has an
  exact vue of PMR.
- Reevaluate state of HW-mapped, level triggered interrupts
  on enable.
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
…OL_MF_STRICT were specified

When both MPOL_MF_MOVE* and MPOL_MF_STRICT was specified, mbind() should
try best to migrate misplaced pages, if some of the pages could not be
migrated, then return -EIO.

There are three different sub-cases:
 1. vma is not migratable
 2. vma is migratable, but there are unmovable pages
 3. vma is migratable, pages are movable, but migrate_pages() fails

If #1 happens, kernel would just abort immediately, then return -EIO,
after a7f40cf ("mm: mempolicy: make mbind() return -EIO when
MPOL_MF_STRICT is specified").

If #3 happens, kernel would set policy and migrate pages with
best-effort, but won't rollback the migrated pages and reset the policy
back.

Before that commit, they behaves in the same way.  It'd better to keep
their behavior consistent.  But, rolling back the migrated pages and
resetting the policy back sounds not feasible, so just make #1 behave as
same as #3.

Userspace will know that not everything was successfully migrated (via
-EIO), and can take whatever steps it deems necessary - attempt
rollback, determine which exact page(s) are violating the policy, etc.

Make queue_pages_range() return 1 to indicate there are unmovable pages
or vma is not migratable.

The #2 is not handled correctly in the current kernel, the following
patch will fix it.

[yang.shi@linux.alibaba.com: fix review comments from Vlastimil]
  Link: http://lkml.kernel.org/r/1563556862-54056-2-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1561162809-59140-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
When running syzkaller internally, we ran into the below bug on 4.9.x
kernel:

  kernel BUG at mm/huge_memory.c:2124!
  invalid opcode: 0000 [#1] SMP KASAN
  CPU: 0 PID: 1518 Comm: syz-executor107 Not tainted 4.9.168+ #2
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011
  task: ffff880067b34900 task.stack: ffff880068998000
  RIP: split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124
  Call Trace:
    split_huge_page include/linux/huge_mm.h:100 [inline]
    queue_pages_pte_range+0x7e1/0x1480 mm/mempolicy.c:538
    walk_pmd_range mm/pagewalk.c:50 [inline]
    walk_pud_range mm/pagewalk.c:90 [inline]
    walk_pgd_range mm/pagewalk.c:116 [inline]
    __walk_page_range+0x44a/0xdb0 mm/pagewalk.c:208
    walk_page_range+0x154/0x370 mm/pagewalk.c:285
    queue_pages_range+0x115/0x150 mm/mempolicy.c:694
    do_mbind mm/mempolicy.c:1241 [inline]
    SYSC_mbind+0x3c3/0x1030 mm/mempolicy.c:1370
    SyS_mbind+0x46/0x60 mm/mempolicy.c:1352
    do_syscall_64+0x1d2/0x600 arch/x86/entry/common.c:282
    entry_SYSCALL_64_after_swapgs+0x5d/0xdb
  Code: c7 80 1c 02 00 e8 26 0a 76 01 <0f> 0b 48 c7 c7 40 46 45 84 e8 4c
  RIP  [<ffffffff81895d6b>] split_huge_page_to_list+0x8fb/0x1030 mm/huge_memory.c:2124
   RSP <ffff88006899f980>

with the below test:

  uint64_t r[1] = {0xffffffffffffffff};

  int main(void)
  {
        syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);
                                intptr_t res = 0;
        res = syscall(__NR_socket, 0x11, 3, 0x300);
        if (res != -1)
                r[0] = res;
        *(uint32_t*)0x20000040 = 0x10000;
        *(uint32_t*)0x20000044 = 1;
        *(uint32_t*)0x20000048 = 0xc520;
        *(uint32_t*)0x2000004c = 1;
        syscall(__NR_setsockopt, r[0], 0x107, 0xd, 0x20000040, 0x10);
        syscall(__NR_mmap, 0x20fed000, 0x10000, 0, 0x8811, r[0], 0);
        *(uint64_t*)0x20000340 = 2;
        syscall(__NR_mbind, 0x20ff9000, 0x4000, 0x4002, 0x20000340, 0x45d4, 3);
        return 0;
  }

Actually the test does:

  mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
  socket(AF_PACKET, SOCK_RAW, 768)        = 3
  setsockopt(3, SOL_PACKET, PACKET_TX_RING, {block_size=65536, block_nr=1, frame_size=50464, frame_nr=1}, 16) = 0
  mmap(0x20fed000, 65536, PROT_NONE, MAP_SHARED|MAP_FIXED|MAP_POPULATE|MAP_DENYWRITE, 3, 0) = 0x20fed000
  mbind(..., MPOL_MF_STRICT|MPOL_MF_MOVE) = 0

The setsockopt() would allocate compound pages (16 pages in this test)
for packet tx ring, then the mmap() would call packet_mmap() to map the
pages into the user address space specified by the mmap() call.

When calling mbind(), it would scan the vma to queue the pages for
migration to the new node.  It would split any huge page since 4.9
doesn't support THP migration, however, the packet tx ring compound
pages are not THP and even not movable.  So, the above bug is triggered.

However, the later kernel is not hit by this issue due to commit
d44d363 ("mm: don't assume anonymous pages have SwapBacked flag"),
which just removes the PageSwapBacked check for a different reason.

But, there is a deeper issue.  According to the semantic of mbind(), it
should return -EIO if MPOL_MF_MOVE or MPOL_MF_MOVE_ALL was specified and
MPOL_MF_STRICT was also specified, but the kernel was unable to move all
existing pages in the range.  The tx ring of the packet socket is
definitely not movable, however, mbind() returns success for this case.

Although the most socket file associates with non-movable pages, but XDP
may have movable pages from gup.  So, it sounds not fine to just check
the underlying file type of vma in vma_migratable().

Change migrate_page_add() to check if the page is movable or not, if it
is unmovable, just return -EIO.  But do not abort pte walk immediately,
since there may be pages off LRU temporarily.  We should migrate other
pages if MPOL_MF_MOVE* is specified.  Set has_unmovable flag if some
paged could not be not moved, then return -EIO for mbind() eventually.

With this change the above test would return -EIO as expected.

[yang.shi@linux.alibaba.com: fix review comments from Vlastimil]
  Link: http://lkml.kernel.org/r/1563556862-54056-3-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1561162809-59140-3-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Since commit e1ab9a4 ("i2c: imx: improve the error handling in
i2c_imx_dma_request()") when booting with the DMA driver as module (such
as CONFIG_FSL_EDMA=m) the following endless clk warnings are seen:

[  153.077831] ------------[ cut here ]------------
[  153.082528] WARNING: CPU: 0 PID: 15 at drivers/clk/clk.c:924 clk_core_disable_lock+0x18/0x24
[  153.093077] i2c0 already disabled
[  153.096416] Modules linked in:
[  153.099521] CPU: 0 PID: 15 Comm: kworker/0:1 Tainted: G        W         5.2.0+ torvalds#321
[  153.107290] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
[  153.113772] Workqueue: events deferred_probe_work_func
[  153.118979] [<c0019560>] (unwind_backtrace) from [<c0014734>] (show_stack+0x10/0x14)
[  153.126778] [<c0014734>] (show_stack) from [<c083f8dc>] (dump_stack+0x9c/0xd4)
[  153.134051] [<c083f8dc>] (dump_stack) from [<c0031154>] (__warn+0xf8/0x124)
[  153.141056] [<c0031154>] (__warn) from [<c0031248>] (warn_slowpath_fmt+0x38/0x48)
[  153.148580] [<c0031248>] (warn_slowpath_fmt) from [<c040fde0>] (clk_core_disable_lock+0x18/0x24)
[  153.157413] [<c040fde0>] (clk_core_disable_lock) from [<c058f520>] (i2c_imx_probe+0x554/0x6ec)
[  153.166076] [<c058f520>] (i2c_imx_probe) from [<c04b9178>] (platform_drv_probe+0x48/0x98)
[  153.174297] [<c04b9178>] (platform_drv_probe) from [<c04b7298>] (really_probe+0x1d8/0x2c0)
[  153.182605] [<c04b7298>] (really_probe) from [<c04b7554>] (driver_probe_device+0x5c/0x174)
[  153.190909] [<c04b7554>] (driver_probe_device) from [<c04b58c8>] (bus_for_each_drv+0x44/0x8c)
[  153.199480] [<c04b58c8>] (bus_for_each_drv) from [<c04b746c>] (__device_attach+0xa0/0x108)
[  153.207782] [<c04b746c>] (__device_attach) from [<c04b65a4>] (bus_probe_device+0x88/0x90)
[  153.215999] [<c04b65a4>] (bus_probe_device) from [<c04b6a04>] (deferred_probe_work_func+0x60/0x90)
[  153.225003] [<c04b6a04>] (deferred_probe_work_func) from [<c004f190>] (process_one_work+0x204/0x634)
[  153.234178] [<c004f190>] (process_one_work) from [<c004f618>] (worker_thread+0x20/0x484)
[  153.242315] [<c004f618>] (worker_thread) from [<c0055c2c>] (kthread+0x118/0x150)
[  153.249758] [<c0055c2c>] (kthread) from [<c00090b4>] (ret_from_fork+0x14/0x20)
[  153.257006] Exception stack(0xdde43fb0 to 0xdde43ff8)
[  153.262095] 3fa0:                                     00000000 00000000 00000000 00000000
[  153.270306] 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[  153.278520] 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[  153.285159] irq event stamp: 3323022
[  153.288787] hardirqs last  enabled at (3323021): [<c0861c4c>] _raw_spin_unlock_irq+0x24/0x2c
[  153.297261] hardirqs last disabled at (3323022): [<c040d7a0>] clk_enable_lock+0x10/0x124
[  153.305392] softirqs last  enabled at (3322092): [<c000a504>] __do_softirq+0x344/0x540
[  153.313352] softirqs last disabled at (3322081): [<c00385c0>] irq_exit+0x10c/0x128
[  153.320946] ---[ end trace a506731ccd9bd703 ]---

This endless clk warnings behaviour is well explained by Andrey Smirnov:

"Allocating DMA after registering I2C adapter can lead to infinite
probing loop, for example, consider the following scenario:

    1. i2c_imx_probe() is called and successfully registers an I2C
       adapter via i2c_add_numbered_adapter()

    2. As a part of i2c_add_numbered_adapter() new I2C slave devices
       are added from DT which results in a call to
       driver_deferred_probe_trigger()

    3. i2c_imx_probe() continues and calls i2c_imx_dma_request() which
       due to lack of proper DMA driver returns -EPROBE_DEFER

    4. i2c_imx_probe() fails, removes I2C adapter and returns
       -EPROBE_DEFER, which places it into deferred probe list

    5. Deferred probe work triggered in #2 above kicks in and calls
       i2c_imx_probe() again thus bringing us to step #1"

So revert commit e1ab9a4 ("i2c: imx: improve the error handling in
i2c_imx_dma_request()") and restore the old behaviour, in order to
avoid regressions on existing setups.

Cc: <stable@vger.kernel.org>
Reported-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reported-by: Russell King <linux@armlinux.org.uk>
Fixes: e1ab9a4 ("i2c: imx: improve the error handling in i2c_imx_dma_request()")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Revert the commit bd293d0. The proper
fix has been made available with commit d0a255e ("loop: set
PF_MEMALLOC_NOIO for the worker thread").

Note that the fix offered by commit bd293d0 doesn't really prevent
the deadlock from occuring - if we look at the stacktrace reported by
Junxiao Bi, we see that it hangs in bit_wait_io and not on the mutex -
i.e. it has already successfully taken the mutex. Changing the mutex
from mutex_lock to mutex_trylock won't help with deadlocks that happen
afterwards.

PID: 474    TASK: ffff8813e11f4600  CPU: 10  COMMAND: "kswapd0"
   #0 [ffff8813dedfb938] __schedule at ffffffff8173f405
   #1 [ffff8813dedfb990] schedule at ffffffff8173fa27
   #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec
   #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186
   #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f
   #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8
   #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81
   #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio]
   #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio]
   #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio]
  #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce
  #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778
  #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f
  #13 [ffff8813dedfbec0] kthread at ffffffff810a8428
  #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Fixes: bd293d0 ("dm bufio: fix deadlock with loop device")
Depends-on: d0a255e ("loop: set PF_MEMALLOC_NOIO for the worker thread")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Pablo Neira Ayuso says:

====================
flow_offload hardware priority fixes

This patchset contains two updates for the flow_offload users:

1) Pass the major tc priority to drivers so they do not have to
   lshift it. This is a preparation patch for the fix coming in
   patch #2.

2) Set the hardware priority from the netfilter basechain priority,
   some drivers break when using the existing hardware priority
   number that is set to zero.

v5: fix patch 2/2 to address a clang warning and to simplify
    the priority mapping.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Aug 31, 2019
Calling ceph_buffer_put() in __ceph_setxattr() may end up freeing the
i_xattrs.prealloc_blob buffer while holding the i_ceph_lock.  This can be
fixed by postponing the call until later, when the lock is released.

The following backtrace was triggered by fstests generic/117.

  BUG: sleeping function called from invalid context at mm/vmalloc.c:2283
  in_atomic(): 1, irqs_disabled(): 0, pid: 650, name: fsstress
  3 locks held by fsstress/650:
   #0: 00000000870a0fe8 (sb_writers#8){.+.+}, at: mnt_want_write+0x20/0x50
   #1: 00000000ba0c4c74 (&type->i_mutex_dir_key#6){++++}, at: vfs_setxattr+0x55/0xa0
   #2: 000000008dfbb3f2 (&(&ci->i_ceph_lock)->rlock){+.+.}, at: __ceph_setxattr+0x297/0x810
  CPU: 1 PID: 650 Comm: fsstress Not tainted 5.2.0+ torvalds#437
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014
  Call Trace:
   dump_stack+0x67/0x90
   ___might_sleep.cold+0x9f/0xb1
   vfree+0x4b/0x60
   ceph_buffer_release+0x1b/0x60
   __ceph_setxattr+0x2b4/0x810
   __vfs_setxattr+0x66/0x80
   __vfs_setxattr_noperm+0x59/0xf0
   vfs_setxattr+0x81/0xa0
   setxattr+0x115/0x230
   ? filename_lookup+0xc9/0x140
   ? rcu_read_lock_sched_held+0x74/0x80
   ? rcu_sync_lockdep_assert+0x2e/0x60
   ? __sb_start_write+0x142/0x1a0
   ? mnt_want_write+0x20/0x50
   path_setxattr+0xba/0xd0
   __x64_sys_lsetxattr+0x24/0x30
   do_syscall_64+0x50/0x1c0
   entry_SYSCALL_64_after_hwframe+0x49/0xbe
  RIP: 0033:0x7ff23514359a

Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
stffrdhrn pushed a commit that referenced this pull request May 15, 2021
Danielle Ratson says:

====================
Fix link_mode derived params functionality

Currently, link_mode parameter derives 3 other link parameters, speed,
lanes and duplex, and the derived information is sent to user space.

Few bugs were found in that functionality.
First, some drivers clear the 'ethtool_link_ksettings' struct in their
get_link_ksettings() callback and cause receiving wrong link mode
information in user space. And also, some drivers can report random
values in the 'link_mode' field and cause general protection fault.

Second, the link parameters are only derived in netlink path so in ioctl
path, we don't any reasonable values.

Third, setting 'speed 10000 lanes 1' fails since the lanes parameter
wasn't set for ETHTOOL_LINK_MODE_10000baseR_FEC_BIT.

Patch #1 solves the first two problems by removing link_mode parameter
and deriving the link parameters in driver instead of ethtool.
Patch #2 solves the third one, by setting the lanes parameter for the
link_mode.

v3:
	* Remove the link_mode parameter in the first patch to solve
	  both two issues from patch#1 and patch#2.
	* Add the second patch to solve the third issue.

v2:
	* Add patch #2.
	* Introduce 'cap_link_mode_supported' instead of adding a
	  validity field to 'ethtool_link_ksettings' struct in patch #1.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request May 15, 2021
The following deadlock is detected:

  truncate -> setattr path is waiting for pending direct IO to be done (inode->i_dio_count become zero) with inode->i_rwsem held (down_write).

  PID: 14827  TASK: ffff881686a9af80  CPU: 20  COMMAND: "ora_p005_hrltd9"
   #0  __schedule at ffffffff818667cc
   #1  schedule at ffffffff81866de6
   #2  inode_dio_wait at ffffffff812a2d04
   #3  ocfs2_setattr at ffffffffc05f322e [ocfs2]
   #4  notify_change at ffffffff812a5a09
   #5  do_truncate at ffffffff812808f5
   #6  do_sys_ftruncate.constprop.18 at ffffffff81280cf2
   #7  sys_ftruncate at ffffffff81280d8e
   #8  do_syscall_64 at ffffffff81003949
   #9  entry_SYSCALL_64_after_hwframe at ffffffff81a001ad

dio completion path is going to complete one direct IO (decrement
inode->i_dio_count), but before that it hung at locking inode->i_rwsem:

   #0  __schedule+700 at ffffffff818667cc
   #1  schedule+54 at ffffffff81866de6
   #2  rwsem_down_write_failed+536 at ffffffff8186aa28
   #3  call_rwsem_down_write_failed+23 at ffffffff8185a1b7
   #4  down_write+45 at ffffffff81869c9d
   #5  ocfs2_dio_end_io_write+180 at ffffffffc05d5444 [ocfs2]
   #6  ocfs2_dio_end_io+85 at ffffffffc05d5a85 [ocfs2]
   #7  dio_complete+140 at ffffffff812c873c
   #8  dio_aio_complete_work+25 at ffffffff812c89f9
   #9  process_one_work+361 at ffffffff810b1889
  #10  worker_thread+77 at ffffffff810b233d
  #11  kthread+261 at ffffffff810b7fd5
  #12  ret_from_fork+62 at ffffffff81a0035e

Thus above forms ABBA deadlock.  The same deadlock was mentioned in
upstream commit 28f5a8a ("ocfs2: should wait dio before inode lock
in ocfs2_setattr()").  It seems that that commit only removed the
cluster lock (the victim of above dead lock) from the ABBA deadlock
party.

End-user visible effects: Process hang in truncate -> ocfs2_setattr path
and other processes hang at ocfs2_dio_end_io_write path.

This is to fix the deadlock itself.  It removes inode_lock() call from
dio completion path to remove the deadlock and add ip_alloc_sem lock in
setattr path to synchronize the inode modifications.

[wen.gang.wang@oracle.com: remove the "had_alloc_lock" as suggested]
  Link: https://lkml.kernel.org/r/20210402171344.1605-1-wen.gang.wang@oracle.com

Link: https://lkml.kernel.org/r/20210331203654.3911-1-wen.gang.wang@oracle.com
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Aug 5, 2021
Static analysis reports this problem

write.c:773:29: warning: Assigned value is garbage or undefined
  mapping->writeback_index = next;
                           ^ ~~~~
The call to afs_writepages_region() can return without setting
next.  So check the function return before using next.

Changes:
 ver #2:
   - Need to fix the range_cyclic case also[1].

Fixes: e87b03f ("afs: Prepare for use of THPs")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com
Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1]
Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk/ # v2
stffrdhrn pushed a commit that referenced this pull request Aug 5, 2021
At btrfs_qgroup_trace_extent_post() we call btrfs_find_all_roots() with a
NULL value as the transaction handle argument, which makes that function
take the commit_root_sem semaphore, which is necessary when we don't hold
a transaction handle or any other mechanism to prevent a transaction
commit from wiping out commit roots.

However btrfs_qgroup_trace_extent_post() can be called in a context where
we are holding a write lock on an extent buffer from a subvolume tree,
namely from btrfs_truncate_inode_items(), called either during truncate
or unlink operations. In this case we end up with a lock inversion problem
because the commit_root_sem is a higher level lock, always supposed to be
acquired before locking any extent buffer.

Lockdep detects this lock inversion problem since we switched the extent
buffer locks from custom locks to semaphores, and when running btrfs/158
from fstests, it reported the following trace:

[ 9057.626435] ======================================================
[ 9057.627541] WARNING: possible circular locking dependency detected
[ 9057.628334] 5.14.0-rc2-btrfs-next-93 #1 Not tainted
[ 9057.628961] ------------------------------------------------------
[ 9057.629867] kworker/u16:4/30781 is trying to acquire lock:
[ 9057.630824] ffff8e2590f58760 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x24/0x110 [btrfs]
[ 9057.632542]
               but task is already holding lock:
[ 9057.633551] ffff8e25582d4b70 (&fs_info->commit_root_sem){++++}-{3:3}, at: iterate_extent_inodes+0x10b/0x280 [btrfs]
[ 9057.635255]
               which lock already depends on the new lock.

[ 9057.636292]
               the existing dependency chain (in reverse order) is:
[ 9057.637240]
               -> #1 (&fs_info->commit_root_sem){++++}-{3:3}:
[ 9057.638138]        down_read+0x46/0x140
[ 9057.638648]        btrfs_find_all_roots+0x41/0x80 [btrfs]
[ 9057.639398]        btrfs_qgroup_trace_extent_post+0x37/0x70 [btrfs]
[ 9057.640283]        btrfs_add_delayed_data_ref+0x418/0x490 [btrfs]
[ 9057.641114]        btrfs_free_extent+0x35/0xb0 [btrfs]
[ 9057.641819]        btrfs_truncate_inode_items+0x424/0xf70 [btrfs]
[ 9057.642643]        btrfs_evict_inode+0x454/0x4f0 [btrfs]
[ 9057.643418]        evict+0xcf/0x1d0
[ 9057.643895]        do_unlinkat+0x1e9/0x300
[ 9057.644525]        do_syscall_64+0x3b/0xc0
[ 9057.645110]        entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 9057.645835]
               -> #0 (btrfs-tree-00){++++}-{3:3}:
[ 9057.646600]        __lock_acquire+0x130e/0x2210
[ 9057.647248]        lock_acquire+0xd7/0x310
[ 9057.647773]        down_read_nested+0x4b/0x140
[ 9057.648350]        __btrfs_tree_read_lock+0x24/0x110 [btrfs]
[ 9057.649175]        btrfs_read_lock_root_node+0x31/0x40 [btrfs]
[ 9057.650010]        btrfs_search_slot+0x537/0xc00 [btrfs]
[ 9057.650849]        scrub_print_warning_inode+0x89/0x370 [btrfs]
[ 9057.651733]        iterate_extent_inodes+0x1e3/0x280 [btrfs]
[ 9057.652501]        scrub_print_warning+0x15d/0x2f0 [btrfs]
[ 9057.653264]        scrub_handle_errored_block.isra.0+0x135f/0x1640 [btrfs]
[ 9057.654295]        scrub_bio_end_io_worker+0x101/0x2e0 [btrfs]
[ 9057.655111]        btrfs_work_helper+0xf8/0x400 [btrfs]
[ 9057.655831]        process_one_work+0x247/0x5a0
[ 9057.656425]        worker_thread+0x55/0x3c0
[ 9057.656993]        kthread+0x155/0x180
[ 9057.657494]        ret_from_fork+0x22/0x30
[ 9057.658030]
               other info that might help us debug this:

[ 9057.659064]  Possible unsafe locking scenario:

[ 9057.659824]        CPU0                    CPU1
[ 9057.660402]        ----                    ----
[ 9057.660988]   lock(&fs_info->commit_root_sem);
[ 9057.661581]                                lock(btrfs-tree-00);
[ 9057.662348]                                lock(&fs_info->commit_root_sem);
[ 9057.663254]   lock(btrfs-tree-00);
[ 9057.663690]
                *** DEADLOCK ***

[ 9057.664437] 4 locks held by kworker/u16:4/30781:
[ 9057.665023]  #0: ffff8e25922a1148 ((wq_completion)btrfs-scrub){+.+.}-{0:0}, at: process_one_work+0x1c7/0x5a0
[ 9057.666260]  #1: ffffabb3451ffe70 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x1c7/0x5a0
[ 9057.667639]  #2: ffff8e25922da198 (&ret->mutex){+.+.}-{3:3}, at: scrub_handle_errored_block.isra.0+0x5d2/0x1640 [btrfs]
[ 9057.669017]  #3: ffff8e25582d4b70 (&fs_info->commit_root_sem){++++}-{3:3}, at: iterate_extent_inodes+0x10b/0x280 [btrfs]
[ 9057.670408]
               stack backtrace:
[ 9057.670976] CPU: 7 PID: 30781 Comm: kworker/u16:4 Not tainted 5.14.0-rc2-btrfs-next-93 #1
[ 9057.672030] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 9057.673492] Workqueue: btrfs-scrub btrfs_work_helper [btrfs]
[ 9057.674258] Call Trace:
[ 9057.674588]  dump_stack_lvl+0x57/0x72
[ 9057.675083]  check_noncircular+0xf3/0x110
[ 9057.675611]  __lock_acquire+0x130e/0x2210
[ 9057.676132]  lock_acquire+0xd7/0x310
[ 9057.676605]  ? __btrfs_tree_read_lock+0x24/0x110 [btrfs]
[ 9057.677313]  ? lock_is_held_type+0xe8/0x140
[ 9057.677849]  down_read_nested+0x4b/0x140
[ 9057.678349]  ? __btrfs_tree_read_lock+0x24/0x110 [btrfs]
[ 9057.679068]  __btrfs_tree_read_lock+0x24/0x110 [btrfs]
[ 9057.679760]  btrfs_read_lock_root_node+0x31/0x40 [btrfs]
[ 9057.680458]  btrfs_search_slot+0x537/0xc00 [btrfs]
[ 9057.681083]  ? _raw_spin_unlock+0x29/0x40
[ 9057.681594]  ? btrfs_find_all_roots_safe+0x11f/0x140 [btrfs]
[ 9057.682336]  scrub_print_warning_inode+0x89/0x370 [btrfs]
[ 9057.683058]  ? btrfs_find_all_roots_safe+0x11f/0x140 [btrfs]
[ 9057.683834]  ? scrub_write_block_to_dev_replace+0xb0/0xb0 [btrfs]
[ 9057.684632]  iterate_extent_inodes+0x1e3/0x280 [btrfs]
[ 9057.685316]  scrub_print_warning+0x15d/0x2f0 [btrfs]
[ 9057.685977]  ? ___ratelimit+0xa4/0x110
[ 9057.686460]  scrub_handle_errored_block.isra.0+0x135f/0x1640 [btrfs]
[ 9057.687316]  scrub_bio_end_io_worker+0x101/0x2e0 [btrfs]
[ 9057.688021]  btrfs_work_helper+0xf8/0x400 [btrfs]
[ 9057.688649]  ? lock_is_held_type+0xe8/0x140
[ 9057.689180]  process_one_work+0x247/0x5a0
[ 9057.689696]  worker_thread+0x55/0x3c0
[ 9057.690175]  ? process_one_work+0x5a0/0x5a0
[ 9057.690731]  kthread+0x155/0x180
[ 9057.691158]  ? set_kthread_struct+0x40/0x40
[ 9057.691697]  ret_from_fork+0x22/0x30

Fix this by making btrfs_find_all_roots() never attempt to lock the
commit_root_sem when it is called from btrfs_qgroup_trace_extent_post().

We can't just pass a non-NULL transaction handle to btrfs_find_all_roots()
from btrfs_qgroup_trace_extent_post(), because that would make backref
lookup not use commit roots and acquire read locks on extent buffers, and
therefore could deadlock when btrfs_qgroup_trace_extent_post() is called
from the btrfs_truncate_inode_items() code path which has acquired a write
lock on an extent buffer of the subvolume btree.

CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
stffrdhrn pushed a commit that referenced this pull request Jun 28, 2022
While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled.  This was causing the
following complaint[1] from gcc v12:

  In file included from include/linux/string.h:253,
                   from include/linux/ceph/ceph_debug.h:7,
                   from fs/ceph/inode.c:2:
  In function 'fortify_memset_chk',
      inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
      inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
  include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
    242 |                         __write_overflow_field(p_size_field, size);
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode).  The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

  perl -p -i -e 's/vfs_inode/netfs.inode/'g \
        `git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
 - Fix a couple of missed name changes due to a disabled cifs option.
 - Rename nfs_i_context to nfs_inode
 - Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
   structs.

[ This also undoes commit 507160f ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
stffrdhrn pushed a commit that referenced this pull request Jun 28, 2022
Hulk Robot reports incorrect sp->rx_count_cooked value in decode_std_command().
This should be caused by the subtracting from sp->rx_count_cooked before.
It seems that sp->rx_count_cooked value is changed to 0, which bypassed the
previous judgment.

The situation is shown below:

         (Thread 1)			|  (Thread 2)
decode_std_command()		| resync_tnc()
...					|
if (rest == 2)			|
	sp->rx_count_cooked -= 2;	|
else if (rest == 3)			| ...
					| sp->rx_count_cooked = 0;
	sp->rx_count_cooked -= 1;	|
for (i = 0; i < sp->rx_count_cooked; i++) // report error
	checksum += sp->cooked_buf[i];

sp->rx_count_cooked is a shared variable but is not protected by a lock.
The same applies to sp->rx_count. This patch adds a lock to fix the bug.

The fail log is shown below:
=======================================================================
UBSAN: array-index-out-of-bounds in drivers/net/hamradio/6pack.c:925:31
index 400 is out of range for type 'unsigned char [400]'
CPU: 3 PID: 7433 Comm: kworker/u10:1 Not tainted 5.18.0-rc5-00163-g4b97bac0756a #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 <TASK>
 dump_stack_lvl+0xcd/0x134
 ubsan_epilogue+0xb/0x50
 __ubsan_handle_out_of_bounds.cold+0x62/0x6c
 sixpack_receive_buf+0xfda/0x1330
 tty_ldisc_receive_buf+0x13e/0x180
 tty_port_default_receive_buf+0x6d/0xa0
 flush_to_ldisc+0x213/0x3f0
 process_one_work+0x98f/0x1620
 worker_thread+0x665/0x1080
 kthread+0x2e9/0x3a0
 ret_from_fork+0x1f/0x30
 ...

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xu Jia <xujia39@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Jun 28, 2022
…/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.19, take #2

- Fix a regression with pKVM when kmemleak is enabled

- Add Oliver Upton as an official KVM/arm64 reviewer
stffrdhrn pushed a commit that referenced this pull request Jul 26, 2022
This was missed in c3ed222 ("NFSv4: Fix free of uninitialized
nfs4_label on referral lookup.") and causes a panic when mounting
with '-o trunkdiscovery':

PID: 1604   TASK: ffff93dac3520000  CPU: 3   COMMAND: "mount.nfs"
 #0 [ffffb79140f738f8] machine_kexec at ffffffffaec64bee
 #1 [ffffb79140f73950] __crash_kexec at ffffffffaeda67fd
 #2 [ffffb79140f73a18] crash_kexec at ffffffffaeda76ed
 #3 [ffffb79140f73a30] oops_end at ffffffffaec2658d
 #4 [ffffb79140f73a50] general_protection at ffffffffaf60111e
    [exception RIP: nfs_fattr_init+0x5]
    RIP: ffffffffc0c18265  RSP: ffffb79140f73b08  RFLAGS: 00010246
    RAX: 0000000000000000  RBX: ffff93dac304a800  RCX: 0000000000000000
    RDX: ffffb79140f73bb0  RSI: ffff93dadc8cbb40  RDI: d03ee11cfaf6bd50
    RBP: ffffb79140f73be8   R8: ffffffffc0691560   R9: 0000000000000006
    R10: ffff93db3ffd3df8  R11: 0000000000000000  R12: ffff93dac4040000
    R13: ffff93dac2848e00  R14: ffffb79140f73b60  R15: ffffb79140f73b30
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #5 [ffffb79140f73b08] _nfs41_proc_get_locations at ffffffffc0c73d53 [nfsv4]
 #6 [ffffb79140f73bf0] nfs4_proc_get_locations at ffffffffc0c83e90 [nfsv4]
 #7 [ffffb79140f73c60] nfs4_discover_trunking at ffffffffc0c83fb7 [nfsv4]
 #8 [ffffb79140f73cd8] nfs_probe_fsinfo at ffffffffc0c0f95f [nfs]
 #9 [ffffb79140f73da0] nfs_probe_server at ffffffffc0c1026a [nfs]
    RIP: 00007f6254fce26e  RSP: 00007ffc69496ac8  RFLAGS: 00000246
    RAX: ffffffffffffffda  RBX: 0000000000000000  RCX: 00007f6254fce26e
    RDX: 00005600220a82a0  RSI: 00005600220a64d0  RDI: 00005600220a6520
    RBP: 00007ffc69496c50   R8: 00005600220a8710   R9: 003035322e323231
    R10: 0000000000000000  R11: 0000000000000246  R12: 00007ffc69496c50
    R13: 00005600220a8440  R14: 0000000000000010  R15: 0000560020650ef9
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

Fixes: c3ed222 ("NFSv4: Fix free of uninitialized nfs4_label on referral lookup.")
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
Since the netlink attribute range validation provides inclusive
checking, the *max* of attribute NL80211_ATTR_MLO_LINK_ID should be
IEEE80211_MLD_MAX_NUM_LINKS - 1 otherwise causing an off-by-one.

One crash stack for demonstration:
==================================================================
BUG: KASAN: wild-memory-access in ieee80211_tx_control_port+0x3b6/0xca0 net/mac80211/tx.c:5939
Read of size 6 at addr 001102080000000c by task fuzzer.386/9508

CPU: 1 PID: 9508 Comm: syz.1.386 Not tainted 6.1.70 #2
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x177/0x231 lib/dump_stack.c:106
 print_report+0xe0/0x750 mm/kasan/report.c:398
 kasan_report+0x139/0x170 mm/kasan/report.c:495
 kasan_check_range+0x287/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 ieee80211_tx_control_port+0x3b6/0xca0 net/mac80211/tx.c:5939
 rdev_tx_control_port net/wireless/rdev-ops.h:761 [inline]
 nl80211_tx_control_port+0x7b3/0xc40 net/wireless/nl80211.c:15453
 genl_family_rcv_msg_doit+0x22e/0x320 net/netlink/genetlink.c:756
 genl_family_rcv_msg net/netlink/genetlink.c:833 [inline]
 genl_rcv_msg+0x539/0x740 net/netlink/genetlink.c:850
 netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2508
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:861
 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
 netlink_unicast+0x74b/0x8c0 net/netlink/af_netlink.c:1352
 netlink_sendmsg+0x882/0xb90 net/netlink/af_netlink.c:1874
 sock_sendmsg_nosec net/socket.c:716 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x5cc/0x8f0 net/socket.c:2499
 ___sys_sendmsg+0x21c/0x290 net/socket.c:2553
 __sys_sendmsg net/socket.c:2582 [inline]
 __do_sys_sendmsg net/socket.c:2591 [inline]
 __se_sys_sendmsg+0x19e/0x270 net/socket.c:2589
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x45/0x90 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Update the policy to ensure correct validation.

Fixes: 7b0a0e3 ("wifi: cfg80211: do some rework towards MLO link APIs")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Suggested-by: Cengiz Can <cengiz.can@canonical.com>
Link: https://patch.msgid.link/20241130170526.96698-1-linma@zju.edu.cn
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
Its used from trace__run(), for the 'perf trace' live mode, i.e. its
strace-like, non-perf.data file processing mode, the most common one.

The trace__run() function will set trace->host using machine__new_host()
that is supposed to give a machine instance representing the running
machine, and since we'll use perf_env__arch_strerrno() to get the right
errno -> string table, we need to use machine->env, so initialize it in
machine__new_host().

Before the patch:

  (gdb) run trace --errno-summary -a sleep 1
  <SNIP>
   Summary of events:

   gvfs-afc-volume (3187), 2 events, 0.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     pselect6               1      0     0.000     0.000     0.000     0.000      0.00%

   GUsbEventThread (3519), 2 events, 0.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     poll                   1      0     0.000     0.000     0.000     0.000      0.00%
  <SNIP>
  Program received signal SIGSEGV, Segmentation fault.
  0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
  478		if (env->arch_strerrno == NULL)
  (gdb) bt
  #0  0x00000000005caba0 in perf_env__arch_strerrno (env=0x0, err=110) at util/env.c:478
  #1  0x00000000004b75d2 in thread__dump_stats (ttrace=0x14f58f0, trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4673
  #2  0x00000000004b78bf in trace__fprintf_thread (fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>, thread=0x10fa0b0, trace=0x7fffffffa5b0) at builtin-trace.c:4708
  #3  0x00000000004b7ad9 in trace__fprintf_thread_summary (trace=0x7fffffffa5b0, fp=0x7ffff6ff74e0 <_IO_2_1_stderr_>) at builtin-trace.c:4747
  #4  0x00000000004b656e in trace__run (trace=0x7fffffffa5b0, argc=2, argv=0x7fffffffde60) at builtin-trace.c:4456
  #5  0x00000000004ba43e in cmd_trace (argc=2, argv=0x7fffffffde60) at builtin-trace.c:5487
  #6  0x00000000004c0414 in run_builtin (p=0xec3068 <commands+648>, argc=5, argv=0x7fffffffde60) at perf.c:351
  #7  0x00000000004c06bb in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:404
  #8  0x00000000004c0814 in run_argv (argcp=0x7fffffffdc4c, argv=0x7fffffffdc40) at perf.c:448
  #9  0x00000000004c0b5d in main (argc=5, argv=0x7fffffffde60) at perf.c:560
  (gdb)

After:

  root@number:~# perf trace -a --errno-summary sleep 1
  <SNIP>
     pw-data-loop (2685), 1410 events, 16.0%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     epoll_wait           188      0   983.428     0.000     5.231    15.595      8.68%
     ioctl                 94      0     0.811     0.004     0.009     0.016      2.82%
     read                 188      0     0.322     0.001     0.002     0.006      5.15%
     write                141      0     0.280     0.001     0.002     0.018      8.39%
     timerfd_settime       94      0     0.138     0.001     0.001     0.007      6.47%

   gnome-control-c (179406), 1848 events, 20.9%

     syscall            calls  errors  total       min       avg       max       stddev
                                       (msec)    (msec)    (msec)    (msec)        (%)
     --------------- --------  ------ -------- --------- --------- ---------     ------
     poll                 222      0   959.577     0.000     4.322    21.414     11.40%
     recvmsg              150      0     0.539     0.001     0.004     0.013      5.12%
     write                300      0     0.442     0.001     0.001     0.007      3.29%
     read                 150      0     0.183     0.001     0.001     0.009      5.53%
     getpid               102      0     0.101     0.000     0.001     0.008      7.82%

  root@number:~#

Fixes: 54373b5 ("perf env: Introduce perf_env__arch_strerrno()")
Reported-by: Veronika Molnarova <vmolnaro@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Veronika Molnarova <vmolnaro@redhat.com>
Acked-by: Michael Petlan <mpetlan@redhat.com>
Tested-by: Michael Petlan <mpetlan@redhat.com>
Link: https://lore.kernel.org/r/Z0XffUgNSv_9OjOi@x1
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
When virtnet_close is followed by virtnet_open, some TX completions can
possibly remain unconsumed, until they are finally processed during the
first NAPI poll after the netdev_tx_reset_queue(), resulting in a crash
[1]. Commit b96ed2c ("virtio_net: move netdev_tx_reset_queue() call
before RX napi enable") was not sufficient to eliminate all BQL crash
cases for virtio-net.

This issue can be reproduced with the latest net-next master by running:
`while :; do ip l set DEV down; ip l set DEV up; done` under heavy network
TX load from inside the machine.

netdev_tx_reset_queue() can actually be dropped from virtnet_open path;
the device is not stopped in any case. For BQL core part, it's just like
traffic nearly ceases to exist for some period. For stall detector added
to BQL, even if virtnet_close could somehow lead to some TX completions
delayed for long, followed by virtnet_open, we can just take it as stall
as mentioned in commit 6025b91 ("net: dqs: add NIC stall detector
based on BQL"). Note also that users can still reset stall_max via sysfs.

So, drop netdev_tx_reset_queue() from virtnet_enable_queue_pair(). This
eliminates the BQL crashes. As a result, netdev_tx_reset_queue() is now
explicitly required in freeze/restore path. This patch adds it to
immediately after free_unused_bufs(), following the rule of thumb:
netdev_tx_reset_queue() should follow any SKB freeing not followed by
netdev_tx_completed_queue(). This seems the most consistent and
streamlined approach, and now netdev_tx_reset_queue() runs whenever
free_unused_bufs() is done.

[1]:
------------[ cut here ]------------
kernel BUG at lib/dynamic_queue_limits.c:99!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 7 UID: 0 PID: 1598 Comm: ip Tainted: G    N 6.12.0net-next_main+ #2
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), \
BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:dql_completed+0x26b/0x290
Code: b7 c2 49 89 e9 44 89 da 89 c6 4c 89 d7 e8 ed 17 47 00 58 65 ff 0d
4d 27 90 7e 0f 85 fd fe ff ff e8 ea 53 8d ff e9 f3 fe ff ff <0f> 0b 01
d2 44 89 d1 29 d1 ba 00 00 00 00 0f 48 ca e9 28 ff ff ff
RSP: 0018:ffffc900002b0d08 EFLAGS: 00010297
RAX: 0000000000000000 RBX: ffff888102398c80 RCX: 0000000080190009
RDX: 0000000000000000 RSI: 000000000000006a RDI: 0000000000000000
RBP: ffff888102398c00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000000ca R11: 0000000000015681 R12: 0000000000000001
R13: ffffc900002b0d68 R14: ffff88811115e000 R15: ffff8881107aca40
FS:  00007f41ded69500(0000) GS:ffff888667dc0000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556ccc2dc1a0 CR3: 0000000104fd8003 CR4: 0000000000772ef0
PKRU: 55555554
Call Trace:
 <IRQ>
 ? die+0x32/0x80
 ? do_trap+0xd9/0x100
 ? dql_completed+0x26b/0x290
 ? dql_completed+0x26b/0x290
 ? do_error_trap+0x6d/0xb0
 ? dql_completed+0x26b/0x290
 ? exc_invalid_op+0x4c/0x60
 ? dql_completed+0x26b/0x290
 ? asm_exc_invalid_op+0x16/0x20
 ? dql_completed+0x26b/0x290
 __free_old_xmit+0xff/0x170 [virtio_net]
 free_old_xmit+0x54/0xc0 [virtio_net]
 virtnet_poll+0xf4/0xe30 [virtio_net]
 ? __update_load_avg_cfs_rq+0x264/0x2d0
 ? update_curr+0x35/0x260
 ? reweight_entity+0x1be/0x260
 __napi_poll.constprop.0+0x28/0x1c0
 net_rx_action+0x329/0x420
 ? enqueue_hrtimer+0x35/0x90
 ? trace_hardirqs_on+0x1d/0x80
 ? kvm_sched_clock_read+0xd/0x20
 ? sched_clock+0xc/0x30
 ? kvm_sched_clock_read+0xd/0x20
 ? sched_clock+0xc/0x30
 ? sched_clock_cpu+0xd/0x1a0
 handle_softirqs+0x138/0x3e0
 do_softirq.part.0+0x89/0xc0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xa7/0xb0
 virtnet_open+0xc8/0x310 [virtio_net]
 __dev_open+0xfa/0x1b0
 __dev_change_flags+0x1de/0x250
 dev_change_flags+0x22/0x60
 do_setlink.isra.0+0x2df/0x10b0
 ? rtnetlink_rcv_msg+0x34f/0x3f0
 ? netlink_rcv_skb+0x54/0x100
 ? netlink_unicast+0x23e/0x390
 ? netlink_sendmsg+0x21e/0x490
 ? ____sys_sendmsg+0x31b/0x350
 ? avc_has_perm_noaudit+0x67/0xf0
 ? cred_has_capability.isra.0+0x75/0x110
 ? __nla_validate_parse+0x5f/0xee0
 ? __pfx___probestub_irq_enable+0x3/0x10
 ? __create_object+0x5e/0x90
 ? security_capable+0x3b/0x70
 rtnl_newlink+0x784/0xaf0
 ? avc_has_perm_noaudit+0x67/0xf0
 ? cred_has_capability.isra.0+0x75/0x110
 ? stack_depot_save_flags+0x24/0x6d0
 ? __pfx_rtnl_newlink+0x10/0x10
 rtnetlink_rcv_msg+0x34f/0x3f0
 ? do_syscall_64+0x6c/0x180
 ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
 ? __pfx_rtnetlink_rcv_msg+0x10/0x10
 netlink_rcv_skb+0x54/0x100
 netlink_unicast+0x23e/0x390
 netlink_sendmsg+0x21e/0x490
 ____sys_sendmsg+0x31b/0x350
 ? copy_msghdr_from_user+0x6d/0xa0
 ___sys_sendmsg+0x86/0xd0
 ? __pte_offset_map+0x17/0x160
 ? preempt_count_add+0x69/0xa0
 ? __call_rcu_common.constprop.0+0x147/0x610
 ? preempt_count_add+0x69/0xa0
 ? preempt_count_add+0x69/0xa0
 ? _raw_spin_trylock+0x13/0x60
 ? trace_hardirqs_on+0x1d/0x80
 __sys_sendmsg+0x66/0xc0
 do_syscall_64+0x6c/0x180
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f41defe5b34
Code: 15 e1 12 0f 00 f7 d8 64 89 02 b8 ff ff ff ff eb bf 0f 1f 44 00 00
f3 0f 1e fa 80 3d 35 95 0f 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00
f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 20 89 55
RSP: 002b:00007ffe5336ecc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f41defe5b34
RDX: 0000000000000000 RSI: 00007ffe5336ed30 RDI: 0000000000000003
RBP: 00007ffe5336eda0 R08: 0000000000000010 R09: 0000000000000001
R10: 00007ffe5336f6f9 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000067452259 R14: 0000556ccc28b040 R15: 0000000000000000
 </TASK>
[...]

Fixes: c8bd1f7 ("virtio_net: add support for Byte Queue Limits")
Cc: <stable@vger.kernel.org> # v6.11+
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
[ pabeni: trimmed possibly troublesome separator ]
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
…nts'

Koichiro Den says:

====================
virtio_net: correct netdev_tx_reset_queue() invocation points

When virtnet_close is followed by virtnet_open, some TX completions can
possibly remain unconsumed, until they are finally processed during the
first NAPI poll after the netdev_tx_reset_queue(), resulting in a crash
[1]. Commit b96ed2c ("virtio_net: move netdev_tx_reset_queue() call
before RX napi enable") was not sufficient to eliminate all BQL crash
scenarios for virtio-net.

This issue can be reproduced with the latest net-next master by running:
`while :; do ip l set DEV down; ip l set DEV up; done` under heavy network
TX load from inside the machine.

This patch series resolves the issue and also addresses similar existing
problems:

(a). Drop netdev_tx_reset_queue() from open/close path. This eliminates the
     BQL crashes due to the problematic open/close path.

(b). As a result of (a), netdev_tx_reset_queue() is now explicitly required
     in freeze/restore path. Add netdev_tx_reset_queue() immediately after
     free_unused_bufs() invocation.

(c). Fix missing resetting in virtnet_tx_resize().
     virtnet_tx_resize() has lacked proper resetting since commit
     c8bd1f7 ("virtio_net: add support for Byte Queue Limits").

(d). Fix missing resetting in the XDP_SETUP_XSK_POOL path.
     Similar to (c), this path lacked proper resetting. Call
     netdev_tx_reset_queue() when virtqueue_reset() has actually recycled
     unused buffers.

This patch series consists of six commits:
  [1/6]: Resolves (a) and (b).                      # also -stable 6.11.y
  [2/6]: Minor fix to make [4/6] streamlined.
  [3/6]: Prerequisite for (c).                      # also -stable 6.11.y
  [4/6]: Resolves (c) (incl. Prerequisite for (d))  # also -stable 6.11.y
  [5/6]: Preresuisite for (d).
  [6/6]: Resolves (d).

Changes for v4:
  - move netdev_tx_reset_queue() out of free_unused_bufs()
  - submit to net, not net-next
Changes for v3:
  - replace 'flushed' argument with 'recycle_done'
Changes for v2:
  - add tx queue resetting for (b) to (d) above

v3: https://lore.kernel.org/all/20241204050724.307544-1-koichiro.den@canonical.com/
v2: https://lore.kernel.org/all/20241203073025.67065-1-koichiro.den@canonical.com/
v1: https://lore.kernel.org/all/20241130181744.3772632-1-koichiro.den@canonical.com/

[1]:
------------[ cut here ]------------
kernel BUG at lib/dynamic_queue_limits.c:99!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 7 UID: 0 PID: 1598 Comm: ip Tainted: G    N 6.12.0net-next_main+ #2
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), \
BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:dql_completed+0x26b/0x290
Code: b7 c2 49 89 e9 44 89 da 89 c6 4c 89 d7 e8 ed 17 47 00 58 65 ff 0d
4d 27 90 7e 0f 85 fd fe ff ff e8 ea 53 8d ff e9 f3 fe ff ff <0f> 0b 01
d2 44 89 d1 29 d1 ba 00 00 00 00 0f 48 ca e9 28 ff ff ff
RSP: 0018:ffffc900002b0d08 EFLAGS: 00010297
RAX: 0000000000000000 RBX: ffff888102398c80 RCX: 0000000080190009
RDX: 0000000000000000 RSI: 000000000000006a RDI: 0000000000000000
RBP: ffff888102398c00 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000000ca R11: 0000000000015681 R12: 0000000000000001
R13: ffffc900002b0d68 R14: ffff88811115e000 R15: ffff8881107aca40
FS:  00007f41ded69500(0000) GS:ffff888667dc0000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556ccc2dc1a0 CR3: 0000000104fd8003 CR4: 0000000000772ef0
PKRU: 55555554
Call Trace:
 <IRQ>
 ? die+0x32/0x80
 ? do_trap+0xd9/0x100
 ? dql_completed+0x26b/0x290
 ? dql_completed+0x26b/0x290
 ? do_error_trap+0x6d/0xb0
 ? dql_completed+0x26b/0x290
 ? exc_invalid_op+0x4c/0x60
 ? dql_completed+0x26b/0x290
 ? asm_exc_invalid_op+0x16/0x20
 ? dql_completed+0x26b/0x290
 __free_old_xmit+0xff/0x170 [virtio_net]
 free_old_xmit+0x54/0xc0 [virtio_net]
 virtnet_poll+0xf4/0xe30 [virtio_net]
 ? __update_load_avg_cfs_rq+0x264/0x2d0
 ? update_curr+0x35/0x260
 ? reweight_entity+0x1be/0x260
 __napi_poll.constprop.0+0x28/0x1c0
 net_rx_action+0x329/0x420
 ? enqueue_hrtimer+0x35/0x90
 ? trace_hardirqs_on+0x1d/0x80
 ? kvm_sched_clock_read+0xd/0x20
 ? sched_clock+0xc/0x30
 ? kvm_sched_clock_read+0xd/0x20
 ? sched_clock+0xc/0x30
 ? sched_clock_cpu+0xd/0x1a0
 handle_softirqs+0x138/0x3e0
 do_softirq.part.0+0x89/0xc0
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xa7/0xb0
 virtnet_open+0xc8/0x310 [virtio_net]
 __dev_open+0xfa/0x1b0
 __dev_change_flags+0x1de/0x250
 dev_change_flags+0x22/0x60
 do_setlink.isra.0+0x2df/0x10b0
 ? rtnetlink_rcv_msg+0x34f/0x3f0
 ? netlink_rcv_skb+0x54/0x100
 ? netlink_unicast+0x23e/0x390
 ? netlink_sendmsg+0x21e/0x490
 ? ____sys_sendmsg+0x31b/0x350
 ? avc_has_perm_noaudit+0x67/0xf0
 ? cred_has_capability.isra.0+0x75/0x110
 ? __nla_validate_parse+0x5f/0xee0
 ? __pfx___probestub_irq_enable+0x3/0x10
 ? __create_object+0x5e/0x90
 ? security_capable+0x3b/0x7�[I0
 rtnl_newlink+0x784/0xaf0
 ? avc_has_perm_noaudit+0x67/0xf0
 ? cred_has_capability.isra.0+0x75/0x110
 ? stack_depot_save_flags+0x24/0x6d0
 ? __pfx_rtnl_newlink+0x10/0x10
 rtnetlink_rcv_msg+0x34f/0x3f0
 ? do_syscall_64+0x6c/0x180
 ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
 ? __pfx_rtnetlink_rcv_msg+0x10/0x10
 netlink_rcv_skb+0x54/0x100
 netlink_unicast+0x23e/0x390
 netlink_sendmsg+0x21e/0x490
 ____sys_sendmsg+0x31b/0x350
 ? copy_msghdr_from_user+0x6d/0xa0
 ___sys_sendmsg+0x86/0xd0
 ? __pte_offset_map+0x17/0x160
 ? preempt_count_add+0x69/0xa0
 ? __call_rcu_common.constprop.0+0x147/0x610
 ? preempt_count_add+0x69/0xa0
 ? preempt_count_add+0x69/0xa0
 ? _raw_spin_trylock+0x13/0x60
 ? trace_hardirqs_on+0x1d/0x80
 __sys_sendmsg+0x66/0xc0
 do_syscall_64+0x6c/0x180
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f41defe5b34
Code: 15 e1 12 0f 00 f7 d8 64 89 02 b8 ff ff ff ff eb bf 0f 1f 44 00 00
f3 0f 1e fa 80 3d 35 95 0f 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00
f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 20 89 55
RSP: 002b:00007ffe5336ecc8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f41defe5b34
RDX: 0000000000000000 RSI: 00007ffe5336ed30 RDI: 0000000000000003
RBP: 00007ffe5336eda0 R08: 0000000000000010 R09: 0000000000000001
R10: 00007ffe5336f6f9 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000067452259 R14: 0000556ccc28b040 R15: 0000000000000000
 </TASK>
[...]
====================

Link: https://patch.msgid.link/20241206011047.923923-1-koichiro.den@canonical.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
…ux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.13, part #2

 - Fix confusion with implicitly-shifted MDCR_EL2 masks breaking
   SPE/TRBE initialization

 - Align nested page table walker with the intended memory attribute
   combining rules of the architecture

 - Prevent userspace from constraining the advertised ASID width,
   avoiding horrors of guest TLBIs not matching the intended context in
   hardware

 - Don't leak references on LPIs when insertion into the translation
   cache fails
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
The vmemmap's, which is used for RV64 with SPARSEMEM_VMEMMAP, page
tables are populated using pmd (page middle directory) hugetables.
However, the pmd allocation is not using the generic mechanism used by
the VMA code (e.g. pmd_alloc()), or the RISC-V specific
create_pgd_mapping()/alloc_pmd_late(). Instead, the vmemmap page table
code allocates a page, and calls vmemmap_set_pmd(). This results in
that the pmd ctor is *not* called, nor would it make sense to do so.

Now, when tearing down a vmemmap page table pmd, the cleanup code
would unconditionally, and incorrectly call the pmd dtor, which
results in a crash (best case).

This issue was found when running the HMM selftests:

  | tools/testing/selftests/mm# ./test_hmm.sh smoke
  | ... # when unloading the test_hmm.ko module
  | page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10915b
  | flags: 0x1000000000000000(node=0|zone=1)
  | raw: 1000000000000000 0000000000000000 dead000000000122 0000000000000000
  | raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
  | page dumped because: VM_BUG_ON_PAGE(ptdesc->pmd_huge_pte)
  | ------------[ cut here ]------------
  | kernel BUG at include/linux/mm.h:3080!
  | Kernel BUG [#1]
  | Modules linked in: test_hmm(-) sch_fq_codel fuse drm drm_panel_orientation_quirks backlight dm_mod
  | CPU: 1 UID: 0 PID: 514 Comm: modprobe Tainted: G        W          6.12.0-00982-gf2a4f1682d07 #2
  | Tainted: [W]=WARN
  | Hardware name: riscv-virtio qemu/qemu, BIOS 2024.10 10/01/2024
  | epc : remove_pgd_mapping+0xbec/0x1070
  |  ra : remove_pgd_mapping+0xbec/0x1070
  | epc : ffffffff80010a68 ra : ffffffff80010a68 sp : ff20000000a73940
  |  gp : ffffffff827b2d88 tp : ff6000008785da40 t0 : ffffffff80fbce04
  |  t1 : 0720072007200720 t2 : 706d756420656761 s0 : ff20000000a73a50
  |  s1 : ff6000008915cff8 a0 : 0000000000000039 a1 : 0000000000000008
  |  a2 : ff600003fff0de20 a3 : 0000000000000000 a4 : 0000000000000000
  |  a5 : 0000000000000000 a6 : c0000000ffffefff a7 : ffffffff824469b8
  |  s2 : ff1c0000022456c0 s3 : ff1ffffffdbfffff s4 : ff6000008915c000
  |  s5 : ff6000008915c000 s6 : ff6000008915c000 s7 : ff1ffffffdc00000
  |  s8 : 0000000000000001 s9 : ff1ffffffdc00000 s10: ffffffff819a31f0
  |  s11: ffffffffffffffff t3 : ffffffff8000c950 t4 : ff60000080244f00
  |  t5 : ff60000080244000 t6 : ff20000000a73708
  | status: 0000000200000120 badaddr: ffffffff80010a68 cause: 0000000000000003
  | [<ffffffff80010a68>] remove_pgd_mapping+0xbec/0x1070
  | [<ffffffff80fd238e>] vmemmap_free+0x14/0x1e
  | [<ffffffff8032e698>] section_deactivate+0x220/0x452
  | [<ffffffff8032ef7e>] sparse_remove_section+0x4a/0x58
  | [<ffffffff802f8700>] __remove_pages+0x7e/0xba
  | [<ffffffff803760d8>] memunmap_pages+0x2bc/0x3fe
  | [<ffffffff02a3ca28>] dmirror_device_remove_chunks+0x2ea/0x518 [test_hmm]
  | [<ffffffff02a3e026>] hmm_dmirror_exit+0x3e/0x1018 [test_hmm]
  | [<ffffffff80102c14>] __riscv_sys_delete_module+0x15a/0x2a6
  | [<ffffffff80fd020c>] do_trap_ecall_u+0x1f2/0x266
  | [<ffffffff80fde0a2>] _new_vmalloc_restore_context_a0+0xc6/0xd2
  | Code: bf51 7597 0184 8593 76a5 854a 4097 0029 80e7 2c00 (9002) 7597
  | ---[ end trace 0000000000000000 ]---
  | Kernel panic - not syncing: Fatal exception in interrupt

Add a check to avoid calling the pmd dtor, if the calling context is
vmemmap_free().

Fixes: c75a74f ("riscv: mm: Add memory hotplugging support")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241120131203.1859787-1-bjorn@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
This reworks hci_cb_list to not use mutex hci_cb_list_lock to avoid bugs
like the bellow:

BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5070, name: kworker/u9:2
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
4 locks held by kworker/u9:2/5070:
 #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline]
 #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335
 #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline]
 #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335
 #2: ffff8880665d0078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xcf/0xae0 net/bluetooth/hci_event.c:6914
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: hci_le_create_big_complete_evt+0xdb/0xae0 net/bluetooth/hci_event.c:6915
CPU: 0 PID: 5070 Comm: kworker/u9:2 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Workqueue: hci0 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 __might_resched+0x5d4/0x780 kernel/sched/core.c:10187
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0xc1/0xd70 kernel/locking/mutex.c:752
 hci_connect_cfm include/net/bluetooth/hci_core.h:2004 [inline]
 hci_le_create_big_complete_evt+0x3d9/0xae0 net/bluetooth/hci_event.c:6939
 hci_event_func net/bluetooth/hci_event.c:7514 [inline]
 hci_event_packet+0xa53/0x1540 net/bluetooth/hci_event.c:7569
 hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4171
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243
 </TASK>

Reported-by: syzbot+2fb0835e0c9cefc34614@syzkaller.appspotmail.com
Tested-by: syzbot+2fb0835e0c9cefc34614@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=2fb0835e0c9cefc34614
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
This fixes the circular locking dependency warning below, by
releasing the socket lock before enterning iso_listen_bis, to
avoid any potential deadlock with hdev lock.

[   75.307983] ======================================================
[   75.307984] WARNING: possible circular locking dependency detected
[   75.307985] 6.12.0-rc6+ torvalds#22 Not tainted
[   75.307987] ------------------------------------------------------
[   75.307987] kworker/u81:2/2623 is trying to acquire lock:
[   75.307988] ffff8fde1769da58 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO)
               at: iso_connect_cfm+0x253/0x840 [bluetooth]
[   75.308021]
               but task is already holding lock:
[   75.308022] ffff8fdd61a10078 (&hdev->lock)
               at: hci_le_per_adv_report_evt+0x47/0x2f0 [bluetooth]
[   75.308053]
               which lock already depends on the new lock.

[   75.308054]
               the existing dependency chain (in reverse order) is:
[   75.308055]
               -> #1 (&hdev->lock){+.+.}-{3:3}:
[   75.308057]        __mutex_lock+0xad/0xc50
[   75.308061]        mutex_lock_nested+0x1b/0x30
[   75.308063]        iso_sock_listen+0x143/0x5c0 [bluetooth]
[   75.308085]        __sys_listen_socket+0x49/0x60
[   75.308088]        __x64_sys_listen+0x4c/0x90
[   75.308090]        x64_sys_call+0x2517/0x25f0
[   75.308092]        do_syscall_64+0x87/0x150
[   75.308095]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   75.308098]
               -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
[   75.308100]        __lock_acquire+0x155e/0x25f0
[   75.308103]        lock_acquire+0xc9/0x300
[   75.308105]        lock_sock_nested+0x32/0x90
[   75.308107]        iso_connect_cfm+0x253/0x840 [bluetooth]
[   75.308128]        hci_connect_cfm+0x6c/0x190 [bluetooth]
[   75.308155]        hci_le_per_adv_report_evt+0x27b/0x2f0 [bluetooth]
[   75.308180]        hci_le_meta_evt+0xe7/0x200 [bluetooth]
[   75.308206]        hci_event_packet+0x21f/0x5c0 [bluetooth]
[   75.308230]        hci_rx_work+0x3ae/0xb10 [bluetooth]
[   75.308254]        process_one_work+0x212/0x740
[   75.308256]        worker_thread+0x1bd/0x3a0
[   75.308258]        kthread+0xe4/0x120
[   75.308259]        ret_from_fork+0x44/0x70
[   75.308261]        ret_from_fork_asm+0x1a/0x30
[   75.308263]
               other info that might help us debug this:

[   75.308264]  Possible unsafe locking scenario:

[   75.308264]        CPU0                CPU1
[   75.308265]        ----                ----
[   75.308265]   lock(&hdev->lock);
[   75.308267]                            lock(sk_lock-
                                                AF_BLUETOOTH-BTPROTO_ISO);
[   75.308268]                            lock(&hdev->lock);
[   75.308269]   lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO);
[   75.308270]
                *** DEADLOCK ***

[   75.308271] 4 locks held by kworker/u81:2/2623:
[   75.308272]  #0: ffff8fdd66e52148 ((wq_completion)hci0#2){+.+.}-{0:0},
                at: process_one_work+0x443/0x740
[   75.308276]  #1: ffffafb488b7fe48 ((work_completion)(&hdev->rx_work)),
                at: process_one_work+0x1ce/0x740
[   75.308280]  #2: ffff8fdd61a10078 (&hdev->lock){+.+.}-{3:3}
                at: hci_le_per_adv_report_evt+0x47/0x2f0 [bluetooth]
[   75.308304]  #3: ffffffffb6ba4900 (rcu_read_lock){....}-{1:2},
                at: hci_connect_cfm+0x29/0x190 [bluetooth]

Fixes: 02171da ("Bluetooth: ISO: Add hcon for listening bis sk")
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
This fixes the circular locking dependency warning below, by reworking
iso_sock_recvmsg, to ensure that the socket lock is always released
before calling a function that locks hdev.

[  561.670344] ======================================================
[  561.670346] WARNING: possible circular locking dependency detected
[  561.670349] 6.12.0-rc6+ torvalds#26 Not tainted
[  561.670351] ------------------------------------------------------
[  561.670353] iso-tester/3289 is trying to acquire lock:
[  561.670355] ffff88811f600078 (&hdev->lock){+.+.}-{3:3},
               at: iso_conn_big_sync+0x73/0x260 [bluetooth]
[  561.670405]
               but task is already holding lock:
[  561.670407] ffff88815af58258 (sk_lock-AF_BLUETOOTH){+.+.}-{0:0},
               at: iso_sock_recvmsg+0xbf/0x500 [bluetooth]
[  561.670450]
               which lock already depends on the new lock.

[  561.670452]
               the existing dependency chain (in reverse order) is:
[  561.670453]
               -> #2 (sk_lock-AF_BLUETOOTH){+.+.}-{0:0}:
[  561.670458]        lock_acquire+0x7c/0xc0
[  561.670463]        lock_sock_nested+0x3b/0xf0
[  561.670467]        bt_accept_dequeue+0x1a5/0x4d0 [bluetooth]
[  561.670510]        iso_sock_accept+0x271/0x830 [bluetooth]
[  561.670547]        do_accept+0x3dd/0x610
[  561.670550]        __sys_accept4+0xd8/0x170
[  561.670553]        __x64_sys_accept+0x74/0xc0
[  561.670556]        x64_sys_call+0x17d6/0x25f0
[  561.670559]        do_syscall_64+0x87/0x150
[  561.670563]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  561.670567]
               -> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}:
[  561.670571]        lock_acquire+0x7c/0xc0
[  561.670574]        lock_sock_nested+0x3b/0xf0
[  561.670577]        iso_sock_listen+0x2de/0xf30 [bluetooth]
[  561.670617]        __sys_listen_socket+0xef/0x130
[  561.670620]        __x64_sys_listen+0xe1/0x190
[  561.670623]        x64_sys_call+0x2517/0x25f0
[  561.670626]        do_syscall_64+0x87/0x150
[  561.670629]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  561.670632]
               -> #0 (&hdev->lock){+.+.}-{3:3}:
[  561.670636]        __lock_acquire+0x32ad/0x6ab0
[  561.670639]        lock_acquire.part.0+0x118/0x360
[  561.670642]        lock_acquire+0x7c/0xc0
[  561.670644]        __mutex_lock+0x18d/0x12f0
[  561.670647]        mutex_lock_nested+0x1b/0x30
[  561.670651]        iso_conn_big_sync+0x73/0x260 [bluetooth]
[  561.670687]        iso_sock_recvmsg+0x3e9/0x500 [bluetooth]
[  561.670722]        sock_recvmsg+0x1d5/0x240
[  561.670725]        sock_read_iter+0x27d/0x470
[  561.670727]        vfs_read+0x9a0/0xd30
[  561.670731]        ksys_read+0x1a8/0x250
[  561.670733]        __x64_sys_read+0x72/0xc0
[  561.670736]        x64_sys_call+0x1b12/0x25f0
[  561.670738]        do_syscall_64+0x87/0x150
[  561.670741]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  561.670744]
               other info that might help us debug this:

[  561.670745] Chain exists of:
&hdev->lock --> sk_lock-AF_BLUETOOTH-BTPROTO_ISO --> sk_lock-AF_BLUETOOTH

[  561.670751]  Possible unsafe locking scenario:

[  561.670753]        CPU0                    CPU1
[  561.670754]        ----                    ----
[  561.670756]   lock(sk_lock-AF_BLUETOOTH);
[  561.670758]                                lock(sk_lock
                                              AF_BLUETOOTH-BTPROTO_ISO);
[  561.670761]                                lock(sk_lock-AF_BLUETOOTH);
[  561.670764]   lock(&hdev->lock);
[  561.670767]
                *** DEADLOCK ***

Fixes: 07a9342 ("Bluetooth: ISO: Send BIG Create Sync via hci_sync")
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
Aishwarya reports that warnings are sometimes seen when running the
ftrace kselftests, e.g.

| WARNING: CPU: 5 PID: 2066 at arch/arm64/kernel/stacktrace.c:141 arch_stack_walk+0x4a0/0x4c0
| Modules linked in:
| CPU: 5 UID: 0 PID: 2066 Comm: ftracetest Not tainted 6.13.0-rc2 #2
| Hardware name: linux,dummy-virt (DT)
| pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : arch_stack_walk+0x4a0/0x4c0
| lr : arch_stack_walk+0x248/0x4c0
| sp : ffff800083643d20
| x29: ffff800083643dd0 x28: ffff00007b891400 x27: ffff00007b891928
| x26: 0000000000000001 x25: 00000000000000c0 x24: ffff800082f39d80
| x23: ffff80008003ee8c x22: ffff80008004baa8 x21: ffff8000800533e0
| x20: ffff800083643e10 x19: ffff80008003eec8 x18: 0000000000000000
| x17: 0000000000000000 x16: ffff800083640000 x15: 0000000000000000
| x14: 02a37a802bbb8a92 x13: 00000000000001a9 x12: 0000000000000001
| x11: ffff800082ffad60 x10: ffff800083643d20 x9 : ffff80008003eed0
| x8 : ffff80008004baa8 x7 : ffff800086f2be80 x6 : ffff0000057cf000
| x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff800086f2b690
| x2 : ffff80008004baa8 x1 : ffff80008004baa8 x0 : ffff80008004baa8
| Call trace:
|  arch_stack_walk+0x4a0/0x4c0 (P)
|  arch_stack_walk+0x248/0x4c0 (L)
|  profile_pc+0x44/0x80
|  profile_tick+0x50/0x80 (F)
|  tick_nohz_handler+0xcc/0x160 (F)
|  __hrtimer_run_queues+0x2ac/0x340 (F)
|  hrtimer_interrupt+0xf4/0x268 (F)
|  arch_timer_handler_virt+0x34/0x60 (F)
|  handle_percpu_devid_irq+0x88/0x220 (F)
|  generic_handle_domain_irq+0x34/0x60 (F)
|  gic_handle_irq+0x54/0x140 (F)
|  call_on_irq_stack+0x24/0x58 (F)
|  do_interrupt_handler+0x88/0x98
|  el1_interrupt+0x34/0x68 (F)
|  el1h_64_irq_handler+0x18/0x28
|  el1h_64_irq+0x6c/0x70
|  queued_spin_lock_slowpath+0x78/0x460 (P)

The warning in question is:

  WARN_ON_ONCE(state->common.pc == orig_pc))

... in kunwind_recover_return_address(), which is triggered when
return_to_handler() is encountered in the trace, but
ftrace_graph_ret_addr() cannot find a corresponding original return
address on the fgraph return stack.

This happens because the stacktrace code encounters an exception
boundary where the LR was not live at the time of the exception, but the
LR happens to contain return_to_handler(); either because the task
recently returned there, or due to unfortunate usage of the LR at a
scratch register. In such cases attempts to recover the return address
via ftrace_graph_ret_addr() may fail, triggering the WARN_ON_ONCE()
above and aborting the unwind (hence the stacktrace terminating after
reporting the PC at the time of the exception).

Handling unreliable LR values in these cases is likely to require some
larger rework, so for the moment avoid this problem by restoring the old
behaviour of skipping the LR at exception boundaries, which the
stacktrace code did prior to commit:

  c2c6b27 ("arm64: stacktrace: unwind exception boundaries")

This commit is effectively a partial revert, keeping the structures and
logic to explicitly identify exception boundaries while still skipping
reporting of the LR. The logic to explicitly identify exception
boundaries is still useful for general robustness and as a building
block for future support for RELIABLE_STACKTRACE.

Fixes: c2c6b27 ("arm64: stacktrace: unwind exception boundaries")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Aishwarya TCV <aishwarya.tcv@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241211140704.2498712-2-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
The arm64 stacktrace code has a few error conditions where a
WARN_ON_ONCE() is triggered before the stacktrace is terminated and an
error is returned to the caller. The conditions shouldn't be triggered
when unwinding the current task, but it is possible to trigger these
when unwinding another task which is not blocked, as the stack of that
task is concurrently modified. Kent reports that these warnings can be
triggered while running filesystem tests on bcachefs, which calls the
stacktrace code directly.

To produce a meaningful stacktrace of another task, the task in question
should be blocked, but the stacktrace code is expected to be robust to
cases where it is not blocked. Note that this is purely about not
unuduly scaring the user and/or crashing the kernel; stacktraces in such
cases are meaningless and may leak kernel secrets from the stack of the
task being unwound.

Ideally we'd pin the task in a blocked state during the unwind, as we do
for /proc/${PID}/wchan since commit:

  42a20f8 ("sched: Add wrapper for get_wchan() to keep task blocked")

... but a bunch of places don't do that, notably /proc/${PID}/stack,
where we don't pin the task in a blocked state, but do restrict the
output to privileged users since commit:

  f8a00ce ("proc: restrict kernel stack dumps to root")

... and so it's possible to trigger these warnings accidentally, e.g. by
reading /proc/*/stack (as root):

| for n in $(seq 1 10); do
|     while true; do cat /proc/*/stack > /dev/null 2>&1; done &
| done
| ------------[ cut here ]------------
| WARNING: CPU: 3 PID: 166 at arch/arm64/kernel/stacktrace.c:207 arch_stack_walk+0x1c8/0x370
| Modules linked in:
| CPU: 3 UID: 0 PID: 166 Comm: cat Not tainted 6.13.0-rc2-00003-g3dafa7a7925d #2
| Hardware name: linux,dummy-virt (DT)
| pstate: 81400005 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
| pc : arch_stack_walk+0x1c8/0x370
| lr : arch_stack_walk+0x1b0/0x370
| sp : ffff800080773890
| x29: ffff800080773930 x28: fff0000005c44500 x27: fff00000058fa038
| x26: 000000007ffff000 x25: 0000000000000000 x24: 0000000000000000
| x23: ffffa35a8d9600ec x22: 0000000000000000 x21: fff00000043a33c0
| x20: ffff800080773970 x19: ffffa35a8d960168 x18: 0000000000000000
| x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
| x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
| x8 : ffff8000807738e0 x7 : ffff8000806e3800 x6 : ffff8000806e3818
| x5 : ffff800080773920 x4 : ffff8000806e4000 x3 : ffff8000807738e0
| x2 : 0000000000000018 x1 : ffff8000806e3800 x0 : 0000000000000000
| Call trace:
|  arch_stack_walk+0x1c8/0x370 (P)
|  stack_trace_save_tsk+0x8c/0x108
|  proc_pid_stack+0xb0/0x134
|  proc_single_show+0x60/0x120
|  seq_read_iter+0x104/0x438
|  seq_read+0xf8/0x140
|  vfs_read+0xc4/0x31c
|  ksys_read+0x70/0x108
|  __arm64_sys_read+0x1c/0x28
|  invoke_syscall+0x48/0x104
|  el0_svc_common.constprop.0+0x40/0xe0
|  do_el0_svc+0x1c/0x28
|  el0_svc+0x30/0xcc
|  el0t_64_sync_handler+0x10c/0x138
|  el0t_64_sync+0x198/0x19c
| ---[ end trace 0000000000000000 ]---

Fix this by only warning when unwinding the current task. When unwinding
another task the error conditions will be handled by returning an error
without producing a warning.

The two warnings in kunwind_next_frame_record_meta() were added recently
as part of commit:

  c2c6b27 ("arm64: stacktrace: unwind exception boundaries")

The warning when recovering the fgraph return address has changed form
many times, but was originally introduced back in commit:

  9f41631 ("arm64: fix unwind_frame() for filtered out fn for function graph tracing")

Fixes: c2c6b27 ("arm64: stacktrace: unwind exception boundaries")
Fixes: 9f41631 ("arm64: fix unwind_frame() for filtered out fn for function graph tracing")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241211140704.2498712-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
The current implementation removes cache tags after disabling ATS,
leading to potential memory leaks and kernel crashes. Specifically,
CACHE_TAG_DEVTLB type cache tags may still remain in the list even
after the domain is freed, causing a use-after-free condition.

This issue really shows up when multiple VFs from different PFs
passed through to a single user-space process via vfio-pci. In such
cases, the kernel may crash with kernel messages like:

 BUG: kernel NULL pointer dereference, address: 0000000000000014
 PGD 19036a067 P4D 1940a3067 PUD 136c9b067 PMD 0
 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
 CPU: 74 UID: 0 PID: 3183 Comm: testCli Not tainted 6.11.9 #2
 RIP: 0010:cache_tag_flush_range+0x9b/0x250
 Call Trace:
  <TASK>
  ? __die+0x1f/0x60
  ? page_fault_oops+0x163/0x590
  ? exc_page_fault+0x72/0x190
  ? asm_exc_page_fault+0x22/0x30
  ? cache_tag_flush_range+0x9b/0x250
  ? cache_tag_flush_range+0x5d/0x250
  intel_iommu_tlb_sync+0x29/0x40
  intel_iommu_unmap_pages+0xfe/0x160
  __iommu_unmap+0xd8/0x1a0
  vfio_unmap_unpin+0x182/0x340 [vfio_iommu_type1]
  vfio_remove_dma+0x2a/0xb0 [vfio_iommu_type1]
  vfio_iommu_type1_ioctl+0xafa/0x18e0 [vfio_iommu_type1]

Move cache_tag_unassign_domain() before iommu_disable_pci_caps() to fix
it.

Fixes: 3b1d9e2 ("iommu/vt-d: Add cache tag assignment interface")
Cc: stable@vger.kernel.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20241129020506.576413-1-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
…s_lock

For storing a value to a queue attribute, the queue_attr_store function
first freezes the queue (->q_usage_counter(io)) and then acquire
->sysfs_lock. This seems not correct as the usual ordering should be to
acquire ->sysfs_lock before freezing the queue. This incorrect ordering
causes the following lockdep splat which we are able to reproduce always
simply by accessing /sys/kernel/debug file using ls command:

[   57.597146] WARNING: possible circular locking dependency detected
[   57.597154] 6.12.0-10553-gb86545e02e8c torvalds#20 Tainted: G        W
[   57.597162] ------------------------------------------------------
[   57.597168] ls/4605 is trying to acquire lock:
[   57.597176] c00000003eb56710 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0x58/0xc0
[   57.597200]
               but task is already holding lock:
[   57.597207] c0000018e27c6810 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: iterate_dir+0x94/0x1d4
[   57.597226]
               which lock already depends on the new lock.

[   57.597233]
               the existing dependency chain (in reverse order) is:
[   57.597241]
               -> #5 (&sb->s_type->i_mutex_key#3){++++}-{4:4}:
[   57.597255]        down_write+0x6c/0x18c
[   57.597264]        start_creating+0xb4/0x24c
[   57.597274]        debugfs_create_dir+0x2c/0x1e8
[   57.597283]        blk_register_queue+0xec/0x294
[   57.597292]        add_disk_fwnode+0x2e4/0x548
[   57.597302]        brd_alloc+0x2c8/0x338
[   57.597309]        brd_init+0x100/0x178
[   57.597317]        do_one_initcall+0x88/0x3e4
[   57.597326]        kernel_init_freeable+0x3cc/0x6e0
[   57.597334]        kernel_init+0x34/0x1cc
[   57.597342]        ret_from_kernel_user_thread+0x14/0x1c
[   57.597350]
               -> #4 (&q->debugfs_mutex){+.+.}-{4:4}:
[   57.597362]        __mutex_lock+0xfc/0x12a0
[   57.597370]        blk_register_queue+0xd4/0x294
[   57.597379]        add_disk_fwnode+0x2e4/0x548
[   57.597388]        brd_alloc+0x2c8/0x338
[   57.597395]        brd_init+0x100/0x178
[   57.597402]        do_one_initcall+0x88/0x3e4
[   57.597410]        kernel_init_freeable+0x3cc/0x6e0
[   57.597418]        kernel_init+0x34/0x1cc
[   57.597426]        ret_from_kernel_user_thread+0x14/0x1c
[   57.597434]
               -> #3 (&q->sysfs_lock){+.+.}-{4:4}:
[   57.597446]        __mutex_lock+0xfc/0x12a0
[   57.597454]        queue_attr_store+0x9c/0x110
[   57.597462]        sysfs_kf_write+0x70/0xb0
[   57.597471]        kernfs_fop_write_iter+0x1b0/0x2ac
[   57.597480]        vfs_write+0x3dc/0x6e8
[   57.597488]        ksys_write+0x84/0x140
[   57.597495]        system_call_exception+0x130/0x360
[   57.597504]        system_call_common+0x160/0x2c4
[   57.597516]
               -> #2 (&q->q_usage_counter(io)torvalds#21){++++}-{0:0}:
[   57.597530]        __submit_bio+0x5ec/0x828
[   57.597538]        submit_bio_noacct_nocheck+0x1e4/0x4f0
[   57.597547]        iomap_readahead+0x2a0/0x448
[   57.597556]        xfs_vm_readahead+0x28/0x3c
[   57.597564]        read_pages+0x88/0x41c
[   57.597571]        page_cache_ra_unbounded+0x1ac/0x2d8
[   57.597580]        filemap_get_pages+0x188/0x984
[   57.597588]        filemap_read+0x13c/0x4bc
[   57.597596]        xfs_file_buffered_read+0x88/0x17c
[   57.597605]        xfs_file_read_iter+0xac/0x158
[   57.597614]        vfs_read+0x2d4/0x3b4
[   57.597622]        ksys_read+0x84/0x144
[   57.597629]        system_call_exception+0x130/0x360
[   57.597637]        system_call_common+0x160/0x2c4
[   57.597647]
               -> #1 (mapping.invalidate_lock#2){++++}-{4:4}:
[   57.597661]        down_read+0x6c/0x220
[   57.597669]        filemap_fault+0x870/0x100c
[   57.597677]        xfs_filemap_fault+0xc4/0x18c
[   57.597684]        __do_fault+0x64/0x164
[   57.597693]        __handle_mm_fault+0x1274/0x1dac
[   57.597702]        handle_mm_fault+0x248/0x484
[   57.597711]        ___do_page_fault+0x428/0xc0c
[   57.597719]        hash__do_page_fault+0x30/0x68
[   57.597727]        do_hash_fault+0x90/0x35c
[   57.597736]        data_access_common_virt+0x210/0x220
[   57.597745]        _copy_from_user+0xf8/0x19c
[   57.597754]        sel_write_load+0x178/0xd54
[   57.597762]        vfs_write+0x108/0x6e8
[   57.597769]        ksys_write+0x84/0x140
[   57.597777]        system_call_exception+0x130/0x360
[   57.597785]        system_call_common+0x160/0x2c4
[   57.597794]
               -> #0 (&mm->mmap_lock){++++}-{4:4}:
[   57.597806]        __lock_acquire+0x17cc/0x2330
[   57.597814]        lock_acquire+0x138/0x400
[   57.597822]        __might_fault+0x7c/0xc0
[   57.597830]        filldir64+0xe8/0x390
[   57.597839]        dcache_readdir+0x80/0x2d4
[   57.597846]        iterate_dir+0xd8/0x1d4
[   57.597855]        sys_getdents64+0x88/0x2d4
[   57.597864]        system_call_exception+0x130/0x360
[   57.597872]        system_call_common+0x160/0x2c4
[   57.597881]
               other info that might help us debug this:

[   57.597888] Chain exists of:
                 &mm->mmap_lock --> &q->debugfs_mutex --> &sb->s_type->i_mutex_key#3

[   57.597905]  Possible unsafe locking scenario:

[   57.597911]        CPU0                    CPU1
[   57.597917]        ----                    ----
[   57.597922]   rlock(&sb->s_type->i_mutex_key#3);
[   57.597932]                                lock(&q->debugfs_mutex);
[   57.597940]                                lock(&sb->s_type->i_mutex_key#3);
[   57.597950]   rlock(&mm->mmap_lock);
[   57.597958]
                *** DEADLOCK ***

[   57.597965] 2 locks held by ls/4605:
[   57.597971]  #0: c0000000137c12f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0xcc/0x154
[   57.597989]  #1: c0000018e27c6810 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: iterate_dir+0x94/0x1d4

Prevent the above lockdep warning by acquiring ->sysfs_lock before
freezing the queue while storing a queue attribute in queue_attr_store
function. Later, we also found[1] another function __blk_mq_update_nr_
hw_queues where we first freeze queue and then acquire the ->sysfs_lock.
So we've also updated lock ordering in __blk_mq_update_nr_hw_queues
function and ensured that in all code paths we follow the correct lock
ordering i.e. acquire ->sysfs_lock before freezing the queue.

[1] https://lore.kernel.org/all/CAFj5m9Ke8+EHKQBs_Nk6hqd=LGXtk4mUxZUN5==ZcCjnZSBwHw@mail.gmail.com/

Reported-by: kjain@linux.ibm.com
Fixes: af28141 ("block: freeze the queue in queue_attr_store")
Tested-by: kjain@linux.ibm.com
Cc: hch@lst.de
Cc: axboe@kernel.dk
Cc: ritesh.list@gmail.com
Cc: ming.lei@redhat.com
Cc: gjoyce@linux.ibm.com
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241210144222.1066229-1-nilay@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
stffrdhrn pushed a commit that referenced this pull request Dec 24, 2024
Guangguan Wang says:

====================
net: several fixes for smc

v1 -> v2:
rewrite patch #2 suggested by Paolo.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
stffrdhrn pushed a commit that referenced this pull request Jan 11, 2025
The mapping VMA address is saved in VAS window struct when the
paste address is mapped. This VMA address is used during migration
to unmap the paste address if the window is active. The paste
address mapping will be removed when the window is closed or with
the munmap(). But the VMA address in the VAS window is not updated
with munmap() which is causing invalid access during migration.

The KASAN report shows:
[16386.254991] BUG: KASAN: slab-use-after-free in reconfig_close_windows+0x1a0/0x4e8
[16386.255043] Read of size 8 at addr c00000014a819670 by task drmgr/696928

[16386.255096] CPU: 29 UID: 0 PID: 696928 Comm: drmgr Kdump: loaded Tainted: G    B              6.11.0-rc5-nxgzip #2
[16386.255128] Tainted: [B]=BAD_PAGE
[16386.255148] Hardware name: IBM,9080-HEX Power11 (architected) 0x820200 0xf000007 of:IBM,FW1110.00 (NH1110_016) hv:phyp pSeries
[16386.255181] Call Trace:
[16386.255202] [c00000016b297660] [c0000000018ad0ac] dump_stack_lvl+0x84/0xe8 (unreliable)
[16386.255246] [c00000016b297690] [c0000000006e8a90] print_report+0x19c/0x764
[16386.255285] [c00000016b297760] [c0000000006e9490] kasan_report+0x128/0x1f8
[16386.255309] [c00000016b297880] [c0000000006eb5c8] __asan_load8+0xac/0xe0
[16386.255326] [c00000016b2978a0] [c00000000013f898] reconfig_close_windows+0x1a0/0x4e8
[16386.255343] [c00000016b297990] [c000000000140e58] vas_migration_handler+0x3a4/0x3fc
[16386.255368] [c00000016b297a90] [c000000000128848] pseries_migrate_partition+0x4c/0x4c4
...

[16386.256136] Allocated by task 696554 on cpu 31 at 16377.277618s:
[16386.256149]  kasan_save_stack+0x34/0x68
[16386.256163]  kasan_save_track+0x34/0x80
[16386.256175]  kasan_save_alloc_info+0x58/0x74
[16386.256196]  __kasan_slab_alloc+0xb8/0xdc
[16386.256209]  kmem_cache_alloc_noprof+0x200/0x3d0
[16386.256225]  vm_area_alloc+0x44/0x150
[16386.256245]  mmap_region+0x214/0x10c4
[16386.256265]  do_mmap+0x5fc/0x750
[16386.256277]  vm_mmap_pgoff+0x14c/0x24c
[16386.256292]  ksys_mmap_pgoff+0x20c/0x348
[16386.256303]  sys_mmap+0xd0/0x160
...

[16386.256350] Freed by task 0 on cpu 31 at 16386.204848s:
[16386.256363]  kasan_save_stack+0x34/0x68
[16386.256374]  kasan_save_track+0x34/0x80
[16386.256384]  kasan_save_free_info+0x64/0x10c
[16386.256396]  __kasan_slab_free+0x120/0x204
[16386.256415]  kmem_cache_free+0x128/0x450
[16386.256428]  vm_area_free_rcu_cb+0xa8/0xd8
[16386.256441]  rcu_do_batch+0x2c8/0xcf0
[16386.256458]  rcu_core+0x378/0x3c4
[16386.256473]  handle_softirqs+0x20c/0x60c
[16386.256495]  do_softirq_own_stack+0x6c/0x88
[16386.256509]  do_softirq_own_stack+0x58/0x88
[16386.256521]  __irq_exit_rcu+0x1a4/0x20c
[16386.256533]  irq_exit+0x20/0x38
[16386.256544]  interrupt_async_exit_prepare.constprop.0+0x18/0x2c
...

[16386.256717] Last potentially related work creation:
[16386.256729]  kasan_save_stack+0x34/0x68
[16386.256741]  __kasan_record_aux_stack+0xcc/0x12c
[16386.256753]  __call_rcu_common.constprop.0+0x94/0xd04
[16386.256766]  vm_area_free+0x28/0x3c
[16386.256778]  remove_vma+0xf4/0x114
[16386.256797]  do_vmi_align_munmap.constprop.0+0x684/0x870
[16386.256811]  __vm_munmap+0xe0/0x1f8
[16386.256821]  sys_munmap+0x54/0x6c
[16386.256830]  system_call_exception+0x1a0/0x4a0
[16386.256841]  system_call_vectored_common+0x15c/0x2ec

[16386.256868] The buggy address belongs to the object at c00000014a819670
                which belongs to the cache vm_area_struct of size 168
[16386.256887] The buggy address is located 0 bytes inside of
                freed 168-byte region [c00000014a819670, c00000014a819718)

[16386.256915] The buggy address belongs to the physical page:
[16386.256928] page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14a81
[16386.256950] memcg:c0000000ba430001
[16386.256961] anon flags: 0x43ffff800000000(node=4|zone=0|lastcpupid=0x7ffff)
[16386.256975] page_type: 0xfdffffff(slab)
[16386.256990] raw: 043ffff800000000 c00000000501c080 0000000000000000 5deadbee00000001
[16386.257003] raw: 0000000000000000 00000000011a011a 00000001fdffffff c0000000ba430001
[16386.257018] page dumped because: kasan: bad access detected

This patch adds close() callback in vas_vm_ops vm_operations_struct
which will be executed during munmap() before freeing VMA. The VMA
address in the VAS window is set to NULL after holding the window
mmap_mutex.

Fixes: 37e6764 ("powerpc/pseries/vas: Add VAS migration handler")
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241214051758.997759-1-haren@linux.ibm.com
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
SMC consists of two sockets: smc_sock and kernel TCP socket.

Currently, there are two ways of creating the sockets, and syzbot reported
a lockdep splat [0] for the newer way introduced by commit d25a92c
("net/smc: Introduce IPPROTO_SMC").

  socket(AF_SMC             , SOCK_STREAM, SMCPROTO_SMC or SMCPROTO_SMC6)
  socket(AF_INET or AF_INET6, SOCK_STREAM, IPPROTO_SMC)

When a socket is allocated, sock_lock_init() sets a lockdep lock class to
sk->sk_lock.slock based on its protocol family.  In the IPPROTO_SMC case,
AF_INET or AF_INET6 lock class is assigned to smc_sock.

The repro sets IPV6_JOIN_ANYCAST for IPv6 UDP and SMC socket and exercises
smc_switch_to_fallback() for IPPROTO_SMC.

  1. smc_switch_to_fallback() is called under lock_sock() and holds
     smc->clcsock_release_lock.

      sk_lock-AF_INET6 -> &smc->clcsock_release_lock
      (sk_lock-AF_SMC)

  2. Setting IPV6_JOIN_ANYCAST to SMC holds smc->clcsock_release_lock
     and calls setsockopt() for the kernel TCP socket, which holds RTNL
     and the kernel socket's lock_sock().

      &smc->clcsock_release_lock -> rtnl_mutex (-> k-sk_lock-AF_INET6)

  3. Setting IPV6_JOIN_ANYCAST to UDP holds RTNL and lock_sock().

      rtnl_mutex -> sk_lock-AF_INET6

Then, lockdep detects a false-positive circular locking,

  .-> sk_lock-AF_INET6 -> &smc->clcsock_release_lock -> rtnl_mutex -.
  `-----------------------------------------------------------------'

but IPPROTO_SMC should have the same locking rule as AF_SMC.

      sk_lock-AF_SMC   -> &smc->clcsock_release_lock -> rtnl_mutex -> k-sk_lock-AF_INET6

Let's set the same lock class for smc_sock.

Given AF_SMC uses the same lock class for SMCPROTO_SMC and SMCPROTO_SMC6,
we do not need to separate the class for AF_INET and AF_INET6.

[0]:
WARNING: possible circular locking dependency detected
6.14.0-rc3-syzkaller-00267-gff202c5028a1 #0 Not tainted

syz.4.1528/11571 is trying to acquire lock:
ffffffff8fef8de8 (rtnl_mutex){+.+.}-{4:4}, at: ipv6_sock_ac_close+0xd9/0x110 net/ipv6/anycast.c:220

but task is already holding lock:
ffff888027f596a8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_clcsock_release+0x75/0xe0 net/smc/smc_close.c:30

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

 -> #2 (&smc->clcsock_release_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       smc_switch_to_fallback+0x2d/0xa00 net/smc/af_smc.c:903
       smc_sendmsg+0x13d/0x520 net/smc/af_smc.c:2781
       sock_sendmsg_nosec net/socket.c:718 [inline]
       __sock_sendmsg net/socket.c:733 [inline]
       ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2573
       ___sys_sendmsg+0x135/0x1e0 net/socket.c:2627
       __sys_sendmsg+0x16e/0x220 net/socket.c:2659
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

 -> #1 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3645
       lock_sock include/net/sock.h:1624 [inline]
       sockopt_lock_sock net/core/sock.c:1133 [inline]
       sockopt_lock_sock+0x54/0x70 net/core/sock.c:1124
       do_ipv6_setsockopt+0x2160/0x4520 net/ipv6/ipv6_sockglue.c:567
       ipv6_setsockopt+0xcb/0x170 net/ipv6/ipv6_sockglue.c:993
       udpv6_setsockopt+0x7d/0xd0 net/ipv6/udp.c:1850
       do_sock_setsockopt+0x222/0x480 net/socket.c:2303
       __sys_setsockopt+0x1a0/0x230 net/socket.c:2328
       __do_sys_setsockopt net/socket.c:2334 [inline]
       __se_sys_setsockopt net/socket.c:2331 [inline]
       __x64_sys_setsockopt+0xbd/0x160 net/socket.c:2331
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

 -> #0 (rtnl_mutex){+.+.}-{4:4}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain kernel/locking/lockdep.c:3906 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       ipv6_sock_ac_close+0xd9/0x110 net/ipv6/anycast.c:220
       inet6_release+0x47/0x70 net/ipv6/af_inet6.c:485
       __sock_release net/socket.c:647 [inline]
       sock_release+0x8e/0x1d0 net/socket.c:675
       smc_clcsock_release+0xb7/0xe0 net/smc/smc_close.c:34
       __smc_release+0x5c2/0x880 net/smc/af_smc.c:301
       smc_release+0x1fc/0x5f0 net/smc/af_smc.c:344
       __sock_release+0xb0/0x270 net/socket.c:647
       sock_close+0x1c/0x30 net/socket.c:1398
       __fput+0x3ff/0xb70 fs/file_table.c:464
       task_work_run+0x14e/0x250 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
       do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  rtnl_mutex --> sk_lock-AF_INET6 --> &smc->clcsock_release_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&smc->clcsock_release_lock);
                               lock(sk_lock-AF_INET6);
                               lock(&smc->clcsock_release_lock);
  lock(rtnl_mutex);

 *** DEADLOCK ***

2 locks held by syz.4.1528/11571:
 #0: ffff888077e88208 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:877 [inline]
 #0: ffff888077e88208 (&sb->s_type->i_mutex_key#10){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:646
 #1: ffff888027f596a8 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_clcsock_release+0x75/0xe0 net/smc/smc_close.c:30

stack backtrace:
CPU: 0 UID: 0 PID: 11571 Comm: syz.4.1528 Not tainted 6.14.0-rc3-syzkaller-00267-gff202c5028a1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x490/0x760 kernel/locking/lockdep.c:2076
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain kernel/locking/lockdep.c:3906 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
 ipv6_sock_ac_close+0xd9/0x110 net/ipv6/anycast.c:220
 inet6_release+0x47/0x70 net/ipv6/af_inet6.c:485
 __sock_release net/socket.c:647 [inline]
 sock_release+0x8e/0x1d0 net/socket.c:675
 smc_clcsock_release+0xb7/0xe0 net/smc/smc_close.c:34
 __smc_release+0x5c2/0x880 net/smc/af_smc.c:301
 smc_release+0x1fc/0x5f0 net/smc/af_smc.c:344
 __sock_release+0xb0/0x270 net/socket.c:647
 sock_close+0x1c/0x30 net/socket.c:1398
 __fput+0x3ff/0xb70 fs/file_table.c:464
 task_work_run+0x14e/0x250 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8b4b38d169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe4efd22d8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000b14a3 RCX: 00007f8b4b38d169
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f8b4b5a7ba0 R08: 0000000000000001 R09: 000000114efd25cf
R10: 00007f8b4b200000 R11: 0000000000000246 R12: 00007f8b4b5a5fac
R13: 00007f8b4b5a5fa0 R14: ffffffffffffffff R15: 00007ffe4efd23f0
 </TASK>

Fixes: d25a92c ("net/smc: Introduce IPPROTO_SMC")
Reported-by: syzbot+be6f4b383534d88989f7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=be6f4b383534d88989f7
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Link: https://patch.msgid.link/20250407170332.26959-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
Ido Schimmel says:

====================
fib_rules: Fix iif / oif matching on L3 master device

Patch #1 fixes a recently reported regression regarding FIB rules that
match on iif / oif being a VRF device.

Patch #2 adds test cases to the FIB rules selftest.
====================

Link: https://patch.msgid.link/20250414172022.242991-1-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
There is a potential deadlock if we do report zones in an IO context, detailed
in below lockdep report. When one process do a report zones and another process
freezes the block device, the report zones side cannot allocate a tag because
the freeze is already started. This can thus result in new block group creation
to hang forever, blocking the write path.

Thankfully, a new block group should be created on empty zones. So, reporting
the zones is not necessary and we can set the write pointer = 0 and load the
zone capacity from the block layer using bdev_zone_capacity() helper.

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc1 torvalds#252 Not tainted
 ------------------------------------------------------
 modprobe/1110 is trying to acquire lock:
 ffff888100ac83e0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x38f/0xb60

 but task is already holding lock:
 ffff8881205b6f20 (&q->q_usage_counter(queue)torvalds#16){++++}-{0:0}, at: sd_remove+0x85/0x130

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #3 (&q->q_usage_counter(queue)torvalds#16){++++}-{0:0}:
        blk_queue_enter+0x3d9/0x500
        blk_mq_alloc_request+0x47d/0x8e0
        scsi_execute_cmd+0x14f/0xb80
        sd_zbc_do_report_zones+0x1c1/0x470
        sd_zbc_report_zones+0x362/0xd60
        blkdev_report_zones+0x1b1/0x2e0
        btrfs_get_dev_zones+0x215/0x7e0 [btrfs]
        btrfs_load_block_group_zone_info+0x6d2/0x2c10 [btrfs]
        btrfs_make_block_group+0x36b/0x870 [btrfs]
        btrfs_create_chunk+0x147d/0x2320 [btrfs]
        btrfs_chunk_alloc+0x2ce/0xcf0 [btrfs]
        start_transaction+0xce6/0x1620 [btrfs]
        btrfs_uuid_scan_kthread+0x4ee/0x5b0 [btrfs]
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&fs_info->dev_replace.rwsem){++++}-{4:4}:
        down_read+0x9b/0x470
        btrfs_map_block+0x2ce/0x2ce0 [btrfs]
        btrfs_submit_chunk+0x2d4/0x16c0 [btrfs]
        btrfs_submit_bbio+0x16/0x30 [btrfs]
        btree_write_cache_pages+0xb5a/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&fs_info->zoned_meta_io_lock){+.+.}-{4:4}:
        __mutex_lock+0x1aa/0x1360
        btree_write_cache_pages+0x252/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
        __lock_acquire+0x2f52/0x5ea0
        lock_acquire+0x1b1/0x540
        __flush_work+0x3ac/0xb60
        wb_shutdown+0x15b/0x1f0
        bdi_unregister+0x172/0x5b0
        del_gendisk+0x841/0xa20
        sd_remove+0x85/0x130
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        __scsi_remove_device+0x272/0x340
        scsi_forget_host+0xf7/0x170
        scsi_remove_host+0xd2/0x2a0
        sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        device_unregister+0x13/0xa0
        sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
        scsi_debug_exit+0x17/0x70 [scsi_debug]
        __do_sys_delete_module.isra.0+0x321/0x520
        do_syscall_64+0x93/0x180
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   (work_completion)(&(&wb->dwork)->work) --> &fs_info->dev_replace.rwsem --> &q->q_usage_counter(queue)torvalds#16

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&q->q_usage_counter(queue)torvalds#16);
                                lock(&fs_info->dev_replace.rwsem);
                                lock(&q->q_usage_counter(queue)torvalds#16);
   lock((work_completion)(&(&wb->dwork)->work));

  *** DEADLOCK ***

 5 locks held by modprobe/1110:
  #0: ffff88811f7bc108 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #1: ffff8881022ee0e0 (&shost->scan_mutex){+.+.}-{4:4}, at: scsi_remove_host+0x20/0x2a0
  #2: ffff88811b4c4378 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #3: ffff8881205b6f20 (&q->q_usage_counter(queue)torvalds#16){++++}-{0:0}, at: sd_remove+0x85/0x130
  #4: ffffffffa3284360 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xda/0xb60

 stack backtrace:
 CPU: 0 UID: 0 PID: 1110 Comm: modprobe Not tainted 6.14.0-rc1 torvalds#252
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6a/0x90
  print_circular_bug.cold+0x1e0/0x274
  check_noncircular+0x306/0x3f0
  ? __pfx_check_noncircular+0x10/0x10
  ? mark_lock+0xf5/0x1650
  ? __pfx_check_irq_usage+0x10/0x10
  ? lockdep_lock+0xca/0x1c0
  ? __pfx_lockdep_lock+0x10/0x10
  __lock_acquire+0x2f52/0x5ea0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx_mark_lock+0x10/0x10
  lock_acquire+0x1b1/0x540
  ? __flush_work+0x38f/0xb60
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  ? __flush_work+0x38f/0xb60
  __flush_work+0x3ac/0xb60
  ? __flush_work+0x38f/0xb60
  ? __pfx_mark_lock+0x10/0x10
  ? __pfx___flush_work+0x10/0x10
  ? __pfx_wq_barrier_func+0x10/0x10
  ? __pfx___might_resched+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  wb_shutdown+0x15b/0x1f0
  bdi_unregister+0x172/0x5b0
  ? __pfx_bdi_unregister+0x10/0x10
  ? up_write+0x1ba/0x510
  del_gendisk+0x841/0xa20
  ? __pfx_del_gendisk+0x10/0x10
  ? _raw_spin_unlock_irqrestore+0x35/0x60
  ? __pm_runtime_resume+0x79/0x110
  sd_remove+0x85/0x130
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  __scsi_remove_device+0x272/0x340
  scsi_forget_host+0xf7/0x170
  scsi_remove_host+0xd2/0x2a0
  sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
  ? kernfs_remove_by_name_ns+0xc0/0xf0
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  ? __pfx___mutex_unlock_slowpath+0x10/0x10
  device_unregister+0x13/0xa0
  sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
  scsi_debug_exit+0x17/0x70 [scsi_debug]
  __do_sys_delete_module.isra.0+0x321/0x520
  ? __pfx___do_sys_delete_module.isra.0+0x10/0x10
  ? __pfx_slab_free_after_rcu_debug+0x10/0x10
  ? kasan_save_stack+0x2c/0x50
  ? kasan_record_aux_stack+0xa3/0xb0
  ? __call_rcu_common.constprop.0+0xc4/0xfb0
  ? kmem_cache_free+0x3a0/0x590
  ? __x64_sys_close+0x78/0xd0
  do_syscall_64+0x93/0x180
  ? lock_is_held_type+0xd5/0x130
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? lockdep_hardirqs_on+0x78/0x100
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? __pfx___call_rcu_common.constprop.0+0x10/0x10
  ? kmem_cache_free+0x3a0/0x590
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  ? __pfx___x64_sys_openat+0x10/0x10
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f436712b68b
 RSP: 002b:00007ffe9f1a8658 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
 RAX: ffffffffffffffda RBX: 00005559b367fd80 RCX: 00007f436712b68b
 RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00005559b367fde8
 RBP: 00007ffe9f1a8680 R08: 1999999999999999 R09: 0000000000000000
 R10: 00007f43671a5fe0 R11: 0000000000000206 R12: 0000000000000000
 R13: 00007ffe9f1a86b0 R14: 0000000000000000 R15: 0000000000000000
  </TASK>

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
CC: <stable@vger.kernel.org> # 6.13+
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
Communicating with the hypervisor using the shared GHCB page requires
clearing the C bit in the mapping of that page. When executing in the
context of the EFI boot services, the page tables are owned by the
firmware, and this manipulation is not possible.

So switch to a different API for accepting memory in SEV-SNP guests, one
which is actually supported at the point during boot where the EFI stub
may need to accept memory, but the SEV-SNP init code has not executed
yet.

For simplicity, also switch the memory acceptance carried out by the
decompressor when not booting via EFI - this only involves the
allocation for the decompressed kernel, and is generally only called
after kexec, as normal boot will jump straight into the kernel from the
EFI stub.

Fixes: 6c32117 ("x86/sev: Add SNP-specific unaccepted memory support")
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Co-developed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Dionna Amalie Glaze <dionnaglaze@google.com>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-efi@vger.kernel.org
Link: https://lore.kernel.org/r/20250404082921.2767593-8-ardb+git@google.com # discussion thread #1
Link: https://lore.kernel.org/r/20250410132850.3708703-2-ardb+git@google.com # discussion thread #2
Link: https://lore.kernel.org/r/20250417202120.1002102-2-ardb+git@google.com # final submission
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
[BUG]
There is a bug report that a syzbot reproducer can lead to the following
busy inode at unmount time:

  BTRFS info (device loop1): last unmount of filesystem 1680000e-3c1e-4c46-84b6-56bd3909af50
  VFS: Busy inodes after unmount of loop1 (btrfs)
  ------------[ cut here ]------------
  kernel BUG at fs/super.c:650!
  Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
  CPU: 0 UID: 0 PID: 48168 Comm: syz-executor Not tainted 6.15.0-rc2-00471-g119009db2674 #2 PREEMPT(full)
  Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
  RIP: 0010:generic_shutdown_super+0x2e9/0x390 fs/super.c:650
  Call Trace:
   <TASK>
   kill_anon_super+0x3a/0x60 fs/super.c:1237
   btrfs_kill_super+0x3b/0x50 fs/btrfs/super.c:2099
   deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
   deactivate_super fs/super.c:506 [inline]
   deactivate_super+0xe2/0x100 fs/super.c:502
   cleanup_mnt+0x21f/0x440 fs/namespace.c:1435
   task_work_run+0x14d/0x240 kernel/task_work.c:227
   resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
   exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
   exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
   __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
   syscall_exit_to_user_mode+0x269/0x290 kernel/entry/common.c:218
   do_syscall_64+0xd4/0x250 arch/x86/entry/syscall_64.c:100
   entry_SYSCALL_64_after_hwframe+0x77/0x7f
   </TASK>

[CAUSE]
When btrfs_alloc_path() failed, btrfs_iget() directly returned without
releasing the inode already allocated by btrfs_iget_locked().

This results the above busy inode and trigger the kernel BUG.

[FIX]
Fix it by calling iget_failed() if btrfs_alloc_path() failed.

If we hit error inside btrfs_read_locked_inode(), it will properly call
iget_failed(), so nothing to worry about.

Although the iget_failed() cleanup inside btrfs_read_locked_inode() is a
break of the normal error handling scheme, let's fix the obvious bug
and backport first, then rework the error handling later.

Reported-by: Penglei Jiang <superman.xpt@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/20250421102425.44431-1-superman.xpt@gmail.com/
Fixes: 7c855e1 ("btrfs: remove conditional path allocation in btrfs_read_locked_inode()")
CC: stable@vger.kernel.org # 6.13+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Penglei Jiang <superman.xpt@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
stffrdhrn pushed a commit that referenced this pull request May 6, 2025
…ux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.15, round #2

 - Single fix for broken usage of 'multi-MIDR' infrastructure in PI
   code, adding an open-coded erratum check for everyone's favorite pile
   of sand: Cavium ThunderX
stffrdhrn pushed a commit that referenced this pull request Jun 7, 2025
…unload

Kernel panic occurs when a devmem TCP socket is closed after NIC module
is unloaded.

This is Devmem TCP unregistration scenarios. number is an order.
(a)netlink socket close    (b)pp destroy    (c)uninstall    result
1                          2                3               OK
1                          3                2               (d)Impossible
2                          1                3               OK
3                          1                2               (e)Kernel panic
2                          3                1               (d)Impossible
3                          2                1               (d)Impossible

(a) netdev_nl_sock_priv_destroy() is called when devmem TCP socket is
    closed.
(b) page_pool_destroy() is called when the interface is down.
(c) mp_ops->uninstall() is called when an interface is unregistered.
(d) There is no scenario in mp_ops->uninstall() is called before
    page_pool_destroy().
    Because unregister_netdevice_many_notify() closes interfaces first
    and then calls mp_ops->uninstall().
(e) netdev_nl_sock_priv_destroy() accesses struct net_device to acquire
    netdev_lock().
    But if the interface module has already been removed, net_device
    pointer is invalid, so it causes kernel panic.

In summary, there are only 3 possible scenarios.
 A. sk close -> pp destroy -> uninstall.
 B. pp destroy -> sk close -> uninstall.
 C. pp destroy -> uninstall -> sk close.

Case C is a kernel panic scenario.

In order to fix this problem, It makes mp_dmabuf_devmem_uninstall() set
binding->dev to NULL.
It indicates an bound net_device was unregistered.

It makes netdev_nl_sock_priv_destroy() do not acquire netdev_lock()
if binding->dev is NULL.

A new binding->lock is added to protect a dev of a binding.
So, lock ordering is like below.
 priv->lock
 netdev_lock(dev)
 binding->lock

Tests:
Scenario A:
    ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \
        -v 7 -t 1 -q 1 &
    pid=$!
    sleep 10
    kill $pid
    ip link set $interface down
    modprobe -rv $module

Scenario B:
    ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \
        -v 7 -t 1 -q 1 &
    pid=$!
    sleep 10
    ip link set $interface down
    kill $pid
    modprobe -rv $module

Scenario C:
    ./ncdevmem -s 192.168.1.4 -c 192.168.1.2 -f $interface -l -p 8000 \
        -v 7 -t 1 -q 1 &
    pid=$!
    sleep 10
    modprobe -rv $module
    sleep 5
    kill $pid

Splat looks like:
Oops: general protection fault, probably for non-canonical address 0xdffffc001fffa9f7: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
KASAN: probably user-memory-access in range [0x00000000fffd4fb8-0x00000000fffd4fbf]
CPU: 0 UID: 0 PID: 2041 Comm: ncdevmem Tainted: G    B   W           6.15.0-rc1+ #2 PREEMPT(undef)  0947ec89efa0fd68838b78e36aa1617e97ff5d7f
Tainted: [B]=BAD_PAGE, [W]=WARN
RIP: 0010:__mutex_lock (./include/linux/sched.h:2244 kernel/locking/mutex.c:400 kernel/locking/mutex.c:443 kernel/locking/mutex.c:605 kernel/locking/mutex.c:746)
Code: ea 03 80 3c 02 00 0f 85 4f 13 00 00 49 8b 1e 48 83 e3 f8 74 6a 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 34 48 89 fa 48 c1 ea 03 <0f> b6 f
RSP: 0018:ffff88826f7ef730 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 00000000fffd4f88 RCX: ffffffffaa9bc811
RDX: 000000001fffa9f7 RSI: 0000000000000008 RDI: 00000000fffd4fbc
RBP: ffff88826f7ef8b0 R08: 0000000000000000 R09: ffffed103e6aa1a4
R10: 0000000000000007 R11: ffff88826f7ef442 R12: fffffbfff669f65e
R13: ffff88812a830040 R14: ffff8881f3550d20 R15: 00000000fffd4f88
FS:  0000000000000000(0000) GS:ffff888866c05000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563bed0cb288 CR3: 00000001a7c98000 CR4: 00000000007506f0
PKRU: 55555554
Call Trace:
<TASK>
 ...
 netdev_nl_sock_priv_destroy (net/core/netdev-genl.c:953 (discriminator 3))
 genl_release (net/netlink/genetlink.c:653 net/netlink/genetlink.c:694 net/netlink/genetlink.c:705)
 ...
 netlink_release (net/netlink/af_netlink.c:737)
 ...
 __sock_release (net/socket.c:647)
 sock_close (net/socket.c:1393)

Fixes: 1d22d30 ("net: drop rtnl_lock for queue_mgmt operations")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250514154028.1062909-1-ap420073@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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