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Sony driver changes to sync with upstream #8

Merged
merged 4 commits into from
Nov 20, 2014
Merged

Sony driver changes to sync with upstream #8

merged 4 commits into from
Nov 20, 2014

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Kontrabant
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These commits do the following:

-Remove a leftover error check that I forgot to remove from commit 47d94a5

-Updates the DS4 touchpad code with the proper measured resolution.

-Switch from stack buffers to kernel allocated buffers for sending and receiving HID reports. Stack buffers cause problems on some configurations as the kernel complains that they aren't DMA capable as reported in https://bugzilla.kernel.org/show_bug.cgi?id=87991

-Add support for a third-party PS3 Bluetooth remote by user request.

These changes sync it with the latest upstream code.

Frank Praznik added 4 commits October 1, 2014 10:07
Remove a leftover if (ret < 0) goto err_stop that wasn't removed
from a previous change as it no longer does anything.

Signed-off-by: Frank Praznik<frank.praznik@oh.rr.com>
The DualShock 4 touchpad has been measured to have a resolution of
44.86 dots/mm which equates to 1920x942.

Signed-off-by: Frank Praznik <frank.praznik@oh.rr.com>
Replace stack buffers with kernel allocated buffers for sending
and receiving HID reports to prevent issues with DMA transfers
on certain hardware.

Output report buffers are allocated at initialization time to avoid
excessive calls to kmalloc and kfree.

Signed-off-by: Frank Praznik <frank.praznik <at> oh.rr.com>
Add vid/pid for the SMK branded third-party PS3 Bluetooth remote and enable
support in the hid-sony driver.

Signed-off-by: Frank Praznik <frank.praznik <at> oh.rr.com>
@Kontrabant Kontrabant changed the title Small Sony driver changes to sync with upstream Sony driver changes to sync with upstream Nov 13, 2014
Plagman added a commit that referenced this pull request Nov 20, 2014
Sony driver changes to sync with upstream
@Plagman Plagman merged commit 5ea6894 into ValveSoftware:alchemist-3.10 Nov 20, 2014
Plagman pushed a commit that referenced this pull request Nov 20, 2014
commit 651e22f upstream.

When performing a consuming read, the ring buffer swaps out a
page from the ring buffer with a empty page and this page that
was swapped out becomes the new reader page. The reader page
is owned by the reader and since it was swapped out of the ring
buffer, writers do not have access to it (there's an exception
to that rule, but it's out of scope for this commit).

When reading the "trace" file, it is a non consuming read, which
means that the data in the ring buffer will not be modified.
When the trace file is opened, a ring buffer iterator is allocated
and writes to the ring buffer are disabled, such that the iterator
will not have issues iterating over the data.

Although the ring buffer disabled writes, it does not disable other
reads, or even consuming reads. If a consuming read happens, then
the iterator is reset and starts reading from the beginning again.

My tests would sometimes trigger this bug on my i386 box:

WARNING: CPU: 0 PID: 5175 at kernel/trace/trace.c:1527 __trace_find_cmdline+0x66/0xaa()
Modules linked in:
CPU: 0 PID: 5175 Comm: grep Not tainted 3.16.0-rc3-test+ #8
Hardware name:                  /DG965MQ, BIOS MQ96510J.86A.0372.2006.0605.1717 06/05/2006
 00000000 00000000 f09c9e1c c18796b3 c1b5d74c f09c9e4c c103a0e3 c1b5154b
 f09c9e78 00001437 c1b5d74c 000005f7 c10bd85a c10bd85a c1cac57c f09c9eb0
 ed0e0000 f09c9e64 c103a185 00000009 f09c9e5c c1b5154b f09c9e78 f09c9e80^M
Call Trace:
 [<c18796b3>] dump_stack+0x4b/0x75
 [<c103a0e3>] warn_slowpath_common+0x7e/0x95
 [<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa
 [<c10bd85a>] ? __trace_find_cmdline+0x66/0xaa
 [<c103a185>] warn_slowpath_fmt+0x33/0x35
 [<c10bd85a>] __trace_find_cmdline+0x66/0xaa^M
 [<c10bed04>] trace_find_cmdline+0x40/0x64
 [<c10c3c16>] trace_print_context+0x27/0xec
 [<c10c4360>] ? trace_seq_printf+0x37/0x5b
 [<c10c0b15>] print_trace_line+0x319/0x39b
 [<c10ba3fb>] ? ring_buffer_read+0x47/0x50
 [<c10c13b1>] s_show+0x192/0x1ab
 [<c10bfd9a>] ? s_next+0x5a/0x7c
 [<c112e76e>] seq_read+0x267/0x34c
 [<c1115a25>] vfs_read+0x8c/0xef
 [<c112e507>] ? seq_lseek+0x154/0x154
 [<c1115ba2>] SyS_read+0x54/0x7f
 [<c188488e>] syscall_call+0x7/0xb
---[ end trace 3f507febd6b4cc83 ]---
>>>> ##### CPU 1 buffer started ####

Which was the __trace_find_cmdline() function complaining about the pid
in the event record being negative.

After adding more test cases, this would trigger more often. Strangely
enough, it would never trigger on a single test, but instead would trigger
only when running all the tests. I believe that was the case because it
required one of the tests to be shutting down via delayed instances while
a new test started up.

After spending several days debugging this, I found that it was caused by
the iterator becoming corrupted. Debugging further, I found out why
the iterator became corrupted. It happened with the rb_iter_reset().

As consuming reads may not read the full reader page, and only part
of it, there's a "read" field to know where the last read took place.
The iterator, must also start at the read position. In the rb_iter_reset()
code, if the reader page was disconnected from the ring buffer, the iterator
would start at the head page within the ring buffer (where writes still
happen). But the mistake there was that it still used the "read" field
to start the iterator on the head page, where it should always start
at zero because readers never read from within the ring buffer where
writes occur.

I originally wrote a patch to have it set the iter->head to 0 instead
of iter->head_page->read, but then I questioned why it wasn't always
setting the iter to point to the reader page, as the reader page is
still valid.  The list_empty(reader_page->list) just means that it was
successful in swapping out. But the reader_page may still have data.

There was a bug report a long time ago that was not reproducible that
had something about trace_pipe (consuming read) not matching trace
(iterator read). This may explain why that happened.

Anyway, the correct answer to this bug is to always use the reader page
an not reset the iterator to inside the writable ring buffer.

Fixes: d769041 "ring_buffer: implement new locking"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fledermaus pushed a commit to fledermaus/steamos_kernel that referenced this pull request Jul 24, 2015
[ Upstream commit 46b0567 ]

Commit 6c81fe7 ("arm64: enable context tracking") did not
update el0_sp_pc to use ct_user_exit, but this appears to have been
unintentional. In commit 6ab6463 ("arm64: adjust el0_sync so
that a function can be called") we made x0 available, and in the return
to userspace we call ct_user_enter in the kernel_exit macro.

Due to this, we currently don't correctly inform RCU of the user->kernel
transition, and may erroneously account for time spent in the kernel as
if we were in an extended quiescent state when CONFIG_CONTEXT_TRACKING
is enabled.

As we do record the kernel->user transition, a userspace application
making accesses from an unaligned stack pointer can demonstrate the
imbalance, provoking the following warning:

------------[ cut here ]------------
WARNING: CPU: 2 PID: 3660 at kernel/context_tracking.c:75 context_tracking_enter+0xd8/0xe4()
Modules linked in:
CPU: 2 PID: 3660 Comm: a.out Not tainted 4.1.0-rc7+ ValveSoftware#8
Hardware name: ARM Juno development board (r0) (DT)
Call trace:
[<ffffffc000089914>] dump_backtrace+0x0/0x124
[<ffffffc000089a48>] show_stack+0x10/0x1c
[<ffffffc0005b3cbc>] dump_stack+0x84/0xc8
[<ffffffc0000b3214>] warn_slowpath_common+0x98/0xd0
[<ffffffc0000b330c>] warn_slowpath_null+0x14/0x20
[<ffffffc00013ada4>] context_tracking_enter+0xd4/0xe4
[<ffffffc0005b534c>] preempt_schedule_irq+0xd4/0x114
[<ffffffc00008561c>] el1_preempt+0x4/0x28
[<ffffffc0001b8040>] exit_files+0x38/0x4c
[<ffffffc0000b5b94>] do_exit+0x430/0x978
[<ffffffc0000b614c>] do_group_exit+0x40/0xd4
[<ffffffc0000c0208>] get_signal+0x23c/0x4f4
[<ffffffc0000890b4>] do_signal+0x1ac/0x518
[<ffffffc000089650>] do_notify_resume+0x5c/0x68
---[ end trace 963c192600337066 ]---

This patch adds the missing ct_user_exit to the el0_sp_pc entry path,
correcting the context tracking for this case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Fixes: 6c81fe7 ("arm64: enable context tracking")
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
fledermaus pushed a commit to fledermaus/steamos_kernel that referenced this pull request Aug 6, 2015
[ Upstream commit 46b0567 ]

Commit 6c81fe7 ("arm64: enable context tracking") did not
update el0_sp_pc to use ct_user_exit, but this appears to have been
unintentional. In commit 6ab6463 ("arm64: adjust el0_sync so
that a function can be called") we made x0 available, and in the return
to userspace we call ct_user_enter in the kernel_exit macro.

Due to this, we currently don't correctly inform RCU of the user->kernel
transition, and may erroneously account for time spent in the kernel as
if we were in an extended quiescent state when CONFIG_CONTEXT_TRACKING
is enabled.

As we do record the kernel->user transition, a userspace application
making accesses from an unaligned stack pointer can demonstrate the
imbalance, provoking the following warning:

------------[ cut here ]------------
WARNING: CPU: 2 PID: 3660 at kernel/context_tracking.c:75 context_tracking_enter+0xd8/0xe4()
Modules linked in:
CPU: 2 PID: 3660 Comm: a.out Not tainted 4.1.0-rc7+ ValveSoftware#8
Hardware name: ARM Juno development board (r0) (DT)
Call trace:
[<ffffffc000089914>] dump_backtrace+0x0/0x124
[<ffffffc000089a48>] show_stack+0x10/0x1c
[<ffffffc0005b3cbc>] dump_stack+0x84/0xc8
[<ffffffc0000b3214>] warn_slowpath_common+0x98/0xd0
[<ffffffc0000b330c>] warn_slowpath_null+0x14/0x20
[<ffffffc00013ada4>] context_tracking_enter+0xd4/0xe4
[<ffffffc0005b534c>] preempt_schedule_irq+0xd4/0x114
[<ffffffc00008561c>] el1_preempt+0x4/0x28
[<ffffffc0001b8040>] exit_files+0x38/0x4c
[<ffffffc0000b5b94>] do_exit+0x430/0x978
[<ffffffc0000b614c>] do_group_exit+0x40/0xd4
[<ffffffc0000c0208>] get_signal+0x23c/0x4f4
[<ffffffc0000890b4>] do_signal+0x1ac/0x518
[<ffffffc000089650>] do_notify_resume+0x5c/0x68
---[ end trace 963c192600337066 ]---

This patch adds the missing ct_user_exit to the el0_sp_pc entry path,
correcting the context tracking for this case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Fixes: 6c81fe7 ("arm64: enable context tracking")
Cc: <stable@vger.kernel.org> # v3.17+
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Plagman pushed a commit that referenced this pull request Sep 16, 2015
[ Upstream commit ecf5fc6 ]

Nikolay has reported a hang when a memcg reclaim got stuck with the
following backtrace:

PID: 18308  TASK: ffff883d7c9b0a30  CPU: 1   COMMAND: "rsync"
  #0 __schedule at ffffffff815ab152
  #1 schedule at ffffffff815ab76e
  #2 schedule_timeout at ffffffff815ae5e5
  #3 io_schedule_timeout at ffffffff815aad6a
  #4 bit_wait_io at ffffffff815abfc6
  #5 __wait_on_bit at ffffffff815abda5
  #6 wait_on_page_bit at ffffffff8111fd4f
  #7 shrink_page_list at ffffffff81135445
  #8 shrink_inactive_list at ffffffff81135845
  #9 shrink_lruvec at ffffffff81135ead
 #10 shrink_zone at ffffffff811360c3
 #11 shrink_zones at ffffffff81136eff
 #12 do_try_to_free_pages at ffffffff8113712f
 #13 try_to_free_mem_cgroup_pages at ffffffff811372be
 #14 try_charge at ffffffff81189423
 #15 mem_cgroup_try_charge at ffffffff8118c6f5
 #16 __add_to_page_cache_locked at ffffffff8112137d
 #17 add_to_page_cache_lru at ffffffff81121618
 #18 pagecache_get_page at ffffffff8112170b
 #19 grow_dev_page at ffffffff811c8297
 #20 __getblk_slow at ffffffff811c91d6
 #21 __getblk_gfp at ffffffff811c92c1
 #22 ext4_ext_grow_indepth at ffffffff8124565c
 #23 ext4_ext_create_new_leaf at ffffffff81246ca8
 #24 ext4_ext_insert_extent at ffffffff81246f09
 #25 ext4_ext_map_blocks at ffffffff8124a848
 #26 ext4_map_blocks at ffffffff8121a5b7
 #27 mpage_map_one_extent at ffffffff8121b1fa
 #28 mpage_map_and_submit_extent at ffffffff8121f07b
 #29 ext4_writepages at ffffffff8121f6d5
 #30 do_writepages at ffffffff8112c490
 #31 __filemap_fdatawrite_range at ffffffff81120199
 #32 filemap_flush at ffffffff8112041c
 #33 ext4_alloc_da_blocks at ffffffff81219da1
 #34 ext4_rename at ffffffff81229b91
 #35 ext4_rename2 at ffffffff81229e32
 #36 vfs_rename at ffffffff811a08a5
 #37 SYSC_renameat2 at ffffffff811a3ffc
 #38 sys_renameat2 at ffffffff811a408e
 #39 sys_rename at ffffffff8119e51e
 #40 system_call_fastpath at ffffffff815afa89

Dave Chinner has properly pointed out that this is a deadlock in the
reclaim code because ext4 doesn't submit pages which are marked by
PG_writeback right away.

The heuristic was introduced by commit e62e384 ("memcg: prevent OOM
with too many dirty pages") and it was applied only when may_enter_fs
was specified.  The code has been changed by c3b94f4 ("memcg:
further prevent OOM with too many dirty pages") which has removed the
__GFP_FS restriction with a reasoning that we do not get into the fs
code.  But this is not sufficient apparently because the fs doesn't
necessarily submit pages marked PG_writeback for IO right away.

ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily
submit the bio.  Instead it tries to map more pages into the bio and
mpage_map_one_extent might trigger memcg charge which might end up
waiting on a page which is marked PG_writeback but hasn't been submitted
yet so we would end up waiting for something that never finishes.

Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2)
before we go to wait on the writeback.  The page fault path, which is
the only path that triggers memcg oom killer since 3.12, shouldn't
require GFP_NOFS and so we shouldn't reintroduce the premature OOM
killer issue which was originally addressed by the heuristic.

As per David Chinner the xfs is doing similar thing since 2.6.15 already
so ext4 is not the only affected filesystem.  Moreover he notes:

: For example: IO completion might require unwritten extent conversion
: which executes filesystem transactions and GFP_NOFS allocations. The
: writeback flag on the pages can not be cleared until unwritten
: extent conversion completes. Hence memory reclaim cannot wait on
: page writeback to complete in GFP_NOFS context because it is not
: safe to do so, memcg reclaim or otherwise.

Cc: stable@vger.kernel.org # 3.9+
[tytso@mit.edu: corrected the control flow]
Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages")
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
johnv-valve pushed a commit that referenced this pull request Nov 18, 2016
[ Upstream commit 0d7b885 ]

Reported by Anton as LTP:munmap01 failing with Illegal Instruction
Exception.

   --------------------->8--------------------------------------
   mmap2(NULL, 24576, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0x200d2000
   munmap(0x200d2000, 24576)               = 0
   --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x200d2000}
   ---
   potentially unexpected fatal signal 4.
   Path: /munmap01
   CPU: 0 PID: 61 Comm: munmap01 Not tainted 3.13.0-g5d5c46d9a556 #8
   task: 9f1a8000 ti: 9f154000 task.ti: 9f154000

   [ECR   ]: 0x00020100 => Illegal Insn
   [EFA   ]: 0x0001354c
   [BLINK ]: 0x200515d4
   [ERET  ]: 0x1354c
       @off 0x1354c in [/munmap01]
       VMA: 0x00010000 to 0x00018000
   [STAT32]: 0x800802c0
   ...
   --------------------->8--------------------------------------

The issue was
1. munmap01 accessed unmapped memory (on purpose) with signal handler
   installed for SIGSEGV

2. The faulting instruction happened to be in Delay Slot
   00011864 <main>:
      11908:	bl.d       13284 <tst_resm>
      1190c:	stb        r16,[r2]

3. kernel sets up the reg file for signal handler and correctly clears
   the DE bit in pt_regs->status32 placeholder

4. However RESTORE_CALLEE_SAVED_USER macro is not adjusted for ARCv2,
   and it over-writes the above with orig/stale value of status32

5. After RTIE, userspace signal handler executes a non branch
   instruction with DE bit set, triggering Illegal Instruction Exception.

Reported-by: Anton Kolesov <akolesov@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
johnv-valve pushed a commit that referenced this pull request Nov 18, 2016
[ Upstream commit 9f8a765 ]

When a user timer instance is continued without the explicit start
beforehand, the system gets eventually zero-division error like:

  divide error: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
  CPU: 1 PID: 27320 Comm: syz-executor Not tainted 4.8.0-rc3-next-20160825+ #8
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
   task: ffff88003c9b2280 task.stack: ffff880027280000
   RIP: 0010:[<ffffffff858e1a6c>]  [<     inline     >] ktime_divns include/linux/ktime.h:195
   RIP: 0010:[<ffffffff858e1a6c>]  [<ffffffff858e1a6c>] snd_hrtimer_callback+0x1bc/0x3c0 sound/core/hrtimer.c:62
  Call Trace:
   <IRQ>
   [<     inline     >] __run_hrtimer kernel/time/hrtimer.c:1238
   [<ffffffff81504335>] __hrtimer_run_queues+0x325/0xe70 kernel/time/hrtimer.c:1302
   [<ffffffff81506ceb>] hrtimer_interrupt+0x18b/0x420 kernel/time/hrtimer.c:1336
   [<ffffffff8126d8df>] local_apic_timer_interrupt+0x6f/0xe0 arch/x86/kernel/apic/apic.c:933
   [<ffffffff86e13056>] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:957
   [<ffffffff86e1210c>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:487
   <EOI>
   .....

Although a similar issue was spotted and a fix patch was merged in
commit [6b760bb: ALSA: timer: fix division by zero after
SNDRV_TIMER_IOCTL_CONTINUE], it seems covering only a part of
iceberg.

In this patch, we fix the issue a bit more drastically.  Basically the
continue of an uninitialized timer is supposed to be a fresh start, so
we do it for user timers.  For the direct snd_timer_continue() call,
there is no way to pass the initial tick value, so we kick out for the
uninitialized case.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
johnv-valve pushed a commit that referenced this pull request Jun 7, 2017
commit a575813 upstream.

Reported by syzkaller:

   BUG: unable to handle kernel paging request at ffffffffc07f6a2e
   IP: report_bug+0x94/0x120
   PGD 348e12067
   P4D 348e12067
   PUD 348e14067
   PMD 3cbd84067
   PTE 80000003f7e87161

   Oops: 0003 [#1] SMP
   CPU: 2 PID: 7091 Comm: kvm_load_guest_ Tainted: G           OE   4.11.0+ #8
   task: ffff92fdfb525400 task.stack: ffffbda6c3d04000
   RIP: 0010:report_bug+0x94/0x120
   RSP: 0018:ffffbda6c3d07b20 EFLAGS: 00010202
    do_trap+0x156/0x170
    do_error_trap+0xa3/0x170
    ? kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? mark_held_locks+0x79/0xa0
    ? retint_kernel+0x10/0x10
    ? trace_hardirqs_off_thunk+0x1a/0x1c
    do_invalid_op+0x20/0x30
    invalid_op+0x1e/0x30
   RIP: 0010:kvm_load_guest_fpu.part.175+0x12a/0x170 [kvm]
    ? kvm_load_guest_fpu.part.175+0x1c/0x170 [kvm]
    kvm_arch_vcpu_ioctl_run+0xed6/0x1b70 [kvm]
    kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? kvm_vcpu_ioctl+0x384/0x780 [kvm]
    ? sched_clock+0x13/0x20
    ? __do_page_fault+0x2a0/0x550
    do_vfs_ioctl+0xa4/0x700
    ? up_read+0x1f/0x40
    ? __do_page_fault+0x2a0/0x550
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x23/0xc2

SDM mentioned that "The MXCSR has several reserved bits, and attempting to write
a 1 to any of these bits will cause a general-protection exception(#GP) to be
generated". The syzkaller forks' testcase overrides xsave area w/ random values
and steps on the reserved bits of MXCSR register. The damaged MXCSR register
values of guest will be restored to SSEx MXCSR register before vmentry. This
patch fixes it by catching userspace override MXCSR register reserved bits w/
random values and bails out immediately.

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
johnv-valve pushed a commit that referenced this pull request Jul 3, 2017
commit 9bc1f09 upstream.

 INFO: task gnome-terminal-:1734 blocked for more than 120 seconds.
       Not tainted 4.12.0-rc4+ #8
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 gnome-terminal- D    0  1734   1015 0x00000000
 Call Trace:
  __schedule+0x3cd/0xb30
  schedule+0x40/0x90
  kvm_async_pf_task_wait+0x1cc/0x270
  ? __vfs_read+0x37/0x150
  ? prepare_to_swait+0x22/0x70
  do_async_page_fault+0x77/0xb0
  ? do_async_page_fault+0x77/0xb0
  async_page_fault+0x28/0x30

This is triggered by running both win7 and win2016 on L1 KVM simultaneously,
and then gives stress to memory on L1, I can observed this hang on L1 when
at least ~70% swap area is occupied on L0.

This is due to async pf was injected to L2 which should be injected to L1,
L2 guest starts receiving pagefault w/ bogus %cr2(apf token from the host
actually), and L1 guest starts accumulating tasks stuck in D state in
kvm_async_pf_task_wait() since missing PAGE_READY async_pfs.

This patch fixes the hang by doing async pf when executing L1 guest.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
johnv-valve pushed a commit that referenced this pull request Jan 5, 2018
[ Upstream commit 87943db ]

Sai reported a warning during some MBA tests:

[  236.755559] ======================================================
[  236.762443] WARNING: possible circular locking dependency detected
[  236.769328] 4.14.0-rc4-yocto-standard #8 Not tainted
[  236.774857] ------------------------------------------------------
[  236.781738] mount/10091 is trying to acquire lock:
[  236.787071]  (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff8117f892>] static_key_enable+0x12/0x30
[  236.797058]
               but task is already holding lock:
[  236.803552]  (&type->s_umount_key#37/1){+.+.}, at: [<ffffffff81208b2f>] sget_userns+0x32f/0x520
[  236.813247]
               which lock already depends on the new lock.

[  236.822353]
               the existing dependency chain (in reverse order) is:
[  236.830686]
               -> #4 (&type->s_umount_key#37/1){+.+.}:
[  236.837756]        __lock_acquire+0x1100/0x11a0
[  236.842799]        lock_acquire+0xdf/0x1d0
[  236.847363]        down_write_nested+0x46/0x80
[  236.852310]        sget_userns+0x32f/0x520
[  236.856873]        kernfs_mount_ns+0x7e/0x1f0
[  236.861728]        rdt_mount+0x30c/0x440
[  236.866096]        mount_fs+0x38/0x150
[  236.870262]        vfs_kern_mount+0x67/0x150
[  236.875015]        do_mount+0x1df/0xd50
[  236.879286]        SyS_mount+0x95/0xe0
[  236.883464]        entry_SYSCALL_64_fastpath+0x18/0xad
[  236.889183]
               -> #3 (rdtgroup_mutex){+.+.}:
[  236.895292]        __lock_acquire+0x1100/0x11a0
[  236.900337]        lock_acquire+0xdf/0x1d0
[  236.904899]        __mutex_lock+0x80/0x8f0
[  236.909459]        mutex_lock_nested+0x1b/0x20
[  236.914407]        intel_rdt_online_cpu+0x3b/0x4a0
[  236.919745]        cpuhp_invoke_callback+0xce/0xb80
[  236.925177]        cpuhp_thread_fun+0x1c5/0x230
[  236.930222]        smpboot_thread_fn+0x11a/0x1e0
[  236.935362]        kthread+0x152/0x190
[  236.939536]        ret_from_fork+0x27/0x40
[  236.944097]
               -> #2 (cpuhp_state-up){+.+.}:
[  236.950199]        __lock_acquire+0x1100/0x11a0
[  236.955241]        lock_acquire+0xdf/0x1d0
[  236.959800]        cpuhp_issue_call+0x12e/0x1c0
[  236.964845]        __cpuhp_setup_state_cpuslocked+0x13b/0x2f0
[  236.971242]        __cpuhp_setup_state+0xa7/0x120
[  236.976483]        page_writeback_init+0x43/0x67
[  236.981623]        pagecache_init+0x38/0x3b
[  236.986281]        start_kernel+0x3c6/0x41a
[  236.990931]        x86_64_start_reservations+0x2a/0x2c
[  236.996650]        x86_64_start_kernel+0x72/0x75
[  237.001793]        verify_cpu+0x0/0xfb
[  237.005966]
               -> #1 (cpuhp_state_mutex){+.+.}:
[  237.012364]        __lock_acquire+0x1100/0x11a0
[  237.017408]        lock_acquire+0xdf/0x1d0
[  237.021969]        __mutex_lock+0x80/0x8f0
[  237.026527]        mutex_lock_nested+0x1b/0x20
[  237.031475]        __cpuhp_setup_state_cpuslocked+0x54/0x2f0
[  237.037777]        __cpuhp_setup_state+0xa7/0x120
[  237.043013]        page_alloc_init+0x28/0x30
[  237.047769]        start_kernel+0x148/0x41a
[  237.052425]        x86_64_start_reservations+0x2a/0x2c
[  237.058145]        x86_64_start_kernel+0x72/0x75
[  237.063284]        verify_cpu+0x0/0xfb
[  237.067456]
               -> #0 (cpu_hotplug_lock.rw_sem){++++}:
[  237.074436]        check_prev_add+0x401/0x800
[  237.079286]        __lock_acquire+0x1100/0x11a0
[  237.084330]        lock_acquire+0xdf/0x1d0
[  237.088890]        cpus_read_lock+0x42/0x90
[  237.093548]        static_key_enable+0x12/0x30
[  237.098496]        rdt_mount+0x406/0x440
[  237.102862]        mount_fs+0x38/0x150
[  237.107035]        vfs_kern_mount+0x67/0x150
[  237.111787]        do_mount+0x1df/0xd50
[  237.116058]        SyS_mount+0x95/0xe0
[  237.120233]        entry_SYSCALL_64_fastpath+0x18/0xad
[  237.125952]
               other info that might help us debug this:

[  237.134867] Chain exists of:
                 cpu_hotplug_lock.rw_sem --> rdtgroup_mutex --> &type->s_umount_key#37/1

[  237.148425]  Possible unsafe locking scenario:

[  237.155015]        CPU0                    CPU1
[  237.160057]        ----                    ----
[  237.165100]   lock(&type->s_umount_key#37/1);
[  237.169952]                                lock(rdtgroup_mutex);
[  237.176641]
lock(&type->s_umount_key#37/1);
[  237.184287]   lock(cpu_hotplug_lock.rw_sem);
[  237.189041]
                *** DEADLOCK ***

When the resctrl filesystem is mounted the locks must be acquired in the
same order as was done when the cpus came online:

     cpu_hotplug_lock before rdtgroup_mutex.

This also requires to switch the static_branch_enable() calls to the
_cpulocked variant because now cpu hotplug lock is held already.

[ tglx: Switched to cpus_read_[un]lock ]

Reported-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Acked-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Link: https://lkml.kernel.org/r/9c41b91bc2f47d9e95b62b213ecdb45623c47a9f.1508490116.git.reinette.chatre@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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