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4.15.rc4 #2

Merged
merged 291 commits into from
Dec 18, 2017
Merged

4.15.rc4 #2

merged 291 commits into from
Dec 18, 2017

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frank-w
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@frank-w frank-w commented Dec 18, 2017

Update

rddunlap and others added 30 commits December 6, 2017 14:55
The coretemp driver build fails when CONFIG_PCI is not enabled because it
uses a function that does not have a stub for that config case, so add the
function stub.

  ../drivers/hwmon/coretemp.c: In function 'adjust_tjmax':
  ../drivers/hwmon/coretemp.c:250:9: error: implicit declaration of function 'pci_get_domain_bus_and_slot' [-Werror=implicit-function-declaration]
    struct pci_dev *host_bridge = pci_get_domain_bus_and_slot(0, 0, devfn);
  ../drivers/hwmon/coretemp.c:250:32: warning: initialization makes pointer from integer without a cast [enabled by default]
    struct pci_dev *host_bridge = pci_get_domain_bus_and_slot(0, 0, devfn);

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
[bhelgaas: identical patch also by Arnd Bergmann <arnd@arndb.de>]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Break the loop if we can't find some address space for a 64bit BAR.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When we have a multi-socket system, each CPU core needs the same setup.
Since this is tricky to do in the fixup code, don't enable a 64bit BAR on
multi-socket systems for now.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
…lculation

Documentation/x86/topology.txt defines smp_num_siblings as "The number of
threads in a core".  Since commit bbb65d2 ("x86: use cpuid vector 0xb
when available for detecting cpu topology") smp_num_siblings is the
maximum number of threads in a core.  If Simultaneous MultiThreading
(SMT) is disabled on a system, smp_num_siblings is 2 and not 1 as
expected.

Use topology_max_smt_threads(), which contains the active numer of threads,
in the __max_logical_packages calculation.

On a single socket, single core, single thread system __max_smt_threads has
not been updated when the __max_logical_packages calculation happens, so its
zero which makes the package estimate fail. Initialize it to one, which is
the minimum number of threads on a core.

[ tglx: Folded the __max_smt_threads fix in ]

Fixes: b4c0a73 ("x86/smpboot: Fix __max_logical_packages estimate")
Reported-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Prarit Bhargava <prarit@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jakub Kicinski <kubakici@wp.pl>
Cc: netdev@vger.kernel.org
Cc: "netdev@vger.kernel.org"
Cc: Clark Williams <williams@redhat.com>
Link: https://lkml.kernel.org/r/20171204164521.17870-1-prarit@redhat.com
Prerequisite for fixing the current problem of instantaneous reboots when a
5-level paging kernel is booted on 4-level paging hardware.

At the same time this change prepares the decompression code to boot-time
switching between 4- and 5-level paging.

[ tglx: Folded the GCC < 5 fix. ]

Fixes: 77ef56e ("x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-mm@kvack.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20171204124059.63515-2-kirill.shutemov@linux.intel.com
If the machine does not support the paging mode for which the kernel was
compiled, the boot process cannot continue.

It's not possible to let the kernel detect the mismatch as it does not even
reach the point where cpu features can be evaluted due to a triple fault in
the KASLR setup.

Instead of instantaneous silent reboot, emit an error message which gives
the user the information why the boot fails.

Fixes: 77ef56e ("x86: Enable 5-level paging support via CONFIG_X86_5LEVEL=y")
Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: linux-mm@kvack.org
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20171204124059.63515-3-kirill.shutemov@linux.intel.com
platform_device_id are not supposed to change at runtime. All functions
working with platform_device_id provided by <linux/platform_device.h>
work with const platform_device_id. So mark the non-const structs as
const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
The alternate port number is used as an array index in the IB
security implementation, invalid values can result in a kernel panic.

Cc: <stable@vger.kernel.org> # v4.12
Fixes: d291f1a ("IB/core: Enforce PKey security on QPs")
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Per the infiniband spec an SMI MAD can have any PKey. Checking the pkey
on SMI MADs is not necessary, and it seems that some older adapters
using the mthca driver don't follow the convention of using the default
PKey, resulting in false denials, or errors querying the PKey cache.

SMI MAD security is still enforced, only agents allowed to manage the
subnet are able to receive or send SMI MADs.

Reported-by: Chris Blake <chrisrblake93@gmail.com>
Cc: <stable@vger.kernel.org> # v4.12
Fixes: 47a2b33 ("IB/core: Enforce security on management datagrams")
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Mistakenly the driver didn't allow RSS hash fields combinations which
involve both IPv4 and IPv6 protocols. This bug caused to failures for
user's use cases for RSS.

Consequently, this patch fixes this bug and allows any combination that
the HW can support.

Additionally, the patch fixes the driver to return an error in case the
user provides an unsupported mask for RSS hash fields.

Fixes: 3078f5f ("IB/mlx4: Add support for RSS QP")
Signed-off-by: Guy Levi <guyle@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
The RDMA netlink core code checks validity of messages by ensuring
that type and operand are in range. It works well for almost all
clients except NLDEV, which has cb_table less than number of operands.

Request to access such operand will trigger the following kernel panic.

This patch updates all places where cb_table is declared for the
consistency, but only NLDEV is actually need it.

general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN
Modules linked in:
CPU: 0 PID: 522 Comm: syz-executor6 Not tainted 4.13.0+ #4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
task: ffff8800657799c0 task.stack: ffff8800695d000
RIP: 0010:rdma_nl_rcv_msg+0x13a/0x4c0
RSP: 0018:ffff8800695d7838 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: 1ffff1000d2baf0b RCX: 00000000704ff4d7
RDX: 0000000000000000 RSI: ffffffff81ddb03c RDI: 00000003827fa6bc
RBP: ffff8800695d7900 R08: ffffffff82ec0578 R09: 0000000000000000
R10: ffff8800695d7900 R11: 0000000000000001 R12: 000000000000001c
R13: ffff880069d31e00 R14: 00000000ffffffff R15: ffff880069d357c0
FS:  00007fee6acb8700(0000) GS:ffff88006ca00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000201a9000 CR3: 0000000059766000 CR4: 00000000000006b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ? rdma_nl_multicast+0x80/0x80
 rdma_nl_rcv+0x36b/0x4d0
 ? ibnl_put_attr+0xc0/0xc0
 netlink_unicast+0x4bd/0x6d0
 ? netlink_sendskb+0x50/0x50
 ? drop_futex_key_refs.isra.4+0x68/0xb0
 netlink_sendmsg+0x9ab/0xbd0
 ? nlmsg_notify+0x140/0x140
 ? wake_up_q+0xa1/0xf0
 ? drop_futex_key_refs.isra.4+0x68/0xb0
 sock_sendmsg+0x88/0xd0
 sock_write_iter+0x228/0x3c0
 ? sock_sendmsg+0xd0/0xd0
 ? do_futex+0x3e5/0xb20
 ? iov_iter_init+0xaf/0x1d0
 __vfs_write+0x46e/0x640
 ? sched_clock_cpu+0x1b/0x190
 ? __vfs_read+0x620/0x620
 ? __fget+0x23a/0x390
 ? rw_verify_area+0xca/0x290
 vfs_write+0x192/0x490
 SyS_write+0xde/0x1c0
 ? SyS_read+0x1c0/0x1c0
 ? trace_hardirqs_on_thunk+0x1a/0x1c
 entry_SYSCALL_64_fastpath+0x18/0xad
RIP: 0033:0x7fee6a74a219
RSP: 002b:00007fee6acb7d58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000638000 RCX: 00007fee6a74a219
RDX: 0000000000000078 RSI: 0000000020141000 RDI: 0000000000000006
RBP: 0000000000000046 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: ffff8800695d7f98
R13: 0000000020141000 R14: 0000000000000006 R15: 00000000ffffffff
Code: d6 48 b8 00 00 00 00 00 fc ff df 66 41 81 e4 ff 03 44 8d 72 ff 4a 8d 3c b5 c0 a6 7f 82 44 89 b5 4c ff ff ff 48 89 f9 48 c1 e9 03 <0f> b6 0c 01 48 89 f8 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85
RIP: rdma_nl_rcv_msg+0x13a/0x4c0 RSP: ffff8800695d7838
---[ end trace ba085d123959c8ec ]---
Kernel panic - not syncing: Fatal exception

Cc: syzkaller <syzkaller@googlegroups.com>
Fixes: b4c598a ("RDMA/netlink: Implement nldev device dumpit calback")
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

Signed-off-by: Doug Ledford <dledford@redhat.com>
In __flush_qp(), the CQ ARMED bit was being cleared regardless of
whether any notification is actually needed.  This resulted in the iser
termination logic getting stuck in ib_drain_sq() because the CQ was not
marked ARMED and thus the drain CQE notification wasn't triggered.

This new bug was exposed when this commit was merged:

commit cbb40fa ("iw_cxgb4: only call the cq comp_handler when the
cq is armed")

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
The added check produces a build error when CONFIG_PROC_FS is
disabled:

net/ipv4/netfilter/ipt_CLUSTERIP.c: In function 'clusterip_net_exit':
net/ipv4/netfilter/ipt_CLUSTERIP.c:822:28: error: 'cn' undeclared (first use in this function)

This moves the variable declaration out of the #ifdef to make it
available to the WARN_ON_ONCE().

Fixes: 613d077 ("netfilter: exit_net cleanup check added")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Before commit 0df21c8 ("scsi: implement .get_budget and .put_budget
for blk-mq"), we run queue after 3ms if queue is idle and SCSI device
queue isn't ready, which is done in handling BLK_STS_RESOURCE. After
commit 0df21c8 is introduced, queue won't be run any more under
this situation.

IO hang is observed when timeout happened, and this patch fixes the IO
hang issue by running queue after delay in scsi_dev_queue_ready, just
like non-mq. This issue can be triggered by the following script[1].

There is another issue which can be covered by running idle queue: when
.get_budget() is called on request coming from hctx->dispatch_list, if
one request just completes during .get_budget(), we can't depend on
SCSI's restart to make progress any more. This patch fixes the race too.

With this patch, we basically recover to previous behaviour (before
commit 0df21c8) of handling idle queue when running out of
resource.

[1] script for test/verify SCSI timeout
rmmod scsi_debug
modprobe scsi_debug max_queue=1

DEVICE=`ls -d /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/* | head -1 | xargs basename`
DISK_DIR=`ls -d /sys/block/$DEVICE/device/scsi_disk/*`

echo "using scsi device $DEVICE"
echo "-1" >/sys/bus/pseudo/drivers/scsi_debug/every_nth
echo "temporary write through" >$DISK_DIR/cache_type
echo "128" >/sys/bus/pseudo/drivers/scsi_debug/opts
echo none > /sys/block/$DEVICE/queue/scheduler
dd if=/dev/$DEVICE of=/dev/null bs=1M iflag=direct count=1 &
sleep 5
echo "0" >/sys/bus/pseudo/drivers/scsi_debug/opts
wait
echo "SUCCESS"

Fixes: 0df21c8 ("scsi: implement .get_budget and .put_budget for blk-mq")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
A regression fix introduced a harmless type mismatch warning:

drivers/scsi/bfa/bfad_bsg.c: In function 'bfad_im_bsg_vendor_request':
drivers/scsi/bfa/bfad_bsg.c:3137:35: error: initialization of 'struct bfad_im_port_s *' from 'long unsigned int' makes pointer from integer without a cast [-Werror=int-conversion]
  struct bfad_im_port_s *im_port = shost->hostdata[0];
                                   ^~~~~
drivers/scsi/bfa/bfad_bsg.c: In function 'bfad_im_bsg_els_ct_request':
drivers/scsi/bfa/bfad_bsg.c:3353:35: error: initialization of 'struct bfad_im_port_s *' from 'long unsigned int' makes pointer from integer without a cast [-Werror=int-conversion]
  struct bfad_im_port_s *im_port = shost->hostdata[0];

This changes the code back to shost_priv() once more, but encapsulates
it in an inline function to document the rather unusual way of
using the private data only as a pointer to the previously allocated
structure.

I did not try to get rid of the extra indirection level entirely,
which would have been rather invasive and required reworking the entire
initialization sequence.

Fixes: 4534982 ("scsi: bfa: fix access to bfad_im_port_s")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Negative child dentry holds reference on inode's alias, it makes
d_prune_aliases() do nothing.

Cc: stable@vger.kernel.org
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Add more stubs to make it build.

Fixes: 81fbfe8 ("ptr_ring: use kmalloc_array()")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Commit ca5beb7 ("dm mpath: micro-optimize the hot path relative to
MPATHF_QUEUE_IF_NO_PATH") caused bio-based DM-multipath to fail mptest's
"test_02_sdev_delete".

Restoring the logic that existed prior to commit ca5beb7 fixes this
bio-based DM-multipath regression.  Also verified all mptest tests pass
with request-based DM-multipath.

This commit effectively reverts commit ca5beb7 -- but it does so
without reintroducing the need to take the m->lock spinlock in
must_push_back_{rq,bio}.

Fixes: ca5beb7 ("dm mpath: micro-optimize the hot path relative to MPATHF_QUEUE_IF_NO_PATH")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When system is under memory pressure it is observed that dm bufio
shrinker often reclaims only one buffer per scan. This change fixes
the following two issues in dm bufio shrinker that cause this behavior:

1. ((nr_to_scan - freed) <= retain_target) condition is used to
terminate slab scan process. This assumes that nr_to_scan is equal
to the LRU size, which might not be correct because do_shrink_slab()
in vmscan.c calculates nr_to_scan using multiple inputs.
As a result when nr_to_scan is less than retain_target (64) the scan
will terminate after the first iteration, effectively reclaiming one
buffer per scan and making scans very inefficient. This hurts vmscan
performance especially because mutex is acquired/released every time
dm_bufio_shrink_scan() is called.
New implementation uses ((LRU size - freed) <= retain_target)
condition for scan termination. LRU size can be safely determined
inside __scan() because this function is called after dm_bufio_lock().

2. do_shrink_slab() uses value returned by dm_bufio_shrink_count() to
determine number of freeable objects in the slab. However dm_bufio
always retains retain_target buffers in its LRU and will terminate
a scan when this mark is reached. Therefore returning the entire LRU size
from dm_bufio_shrink_count() is misleading because that does not
represent the number of freeable objects that slab will reclaim during
a scan. Returning (LRU size - retain_target) better represents the
number of freeable objects in the slab. This way do_shrink_slab()
returns 0 when (LRU size < retain_target) and vmscan will not try to
scan this shrinker avoiding scans that will not reclaim any memory.

Test: tested using Android device running
<AOSP>/system/extras/alloc-stress that generates memory pressure
and causes intensive shrinker scans

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When babble condition happens, the musb controller might automatically
turns off VBUS. On DA8xx platform, the controller generates drvvbus
interrupt for turning off VBUS along with the babble interrupt.

In this case, we should handle the babble interrupt first and recover
from the babble condition.

This change ignores the drvvbus interrupt if babble interrupt is also
generated at the same time, so the babble recovery routine works
properly.

Cc: stable@vger.kernel.org # v3.16+
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is another JMS567-based USB3 UAS enclosure (152d:0578) that fails
with the following error:

[sda] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[sda] tag#0 Sense Key : Illegal Request [current]
[sda] tag#0 Add. Sense: Invalid field in cdb

The issue occurs both with UAS (occasionally) and mass storage
(immediately after mounting a FS on a disk in the enclosure).

Enabling US_FL_BROKEN_FUA quirk solves this issue.

This patch adds an UNUSUAL_DEV with US_FL_BROKEN_FUA for the enclosure
for both UAS and mass storage.

Signed-off-by: David Kozub <zub@linux.fjfi.cvut.cz>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
…ecent gcc with -Werror)

Fixes following build error:
vhci_driver.c: In function 'refresh_imported_device_list':
vhci_driver.c:118:37: error: 'snprintf' output may be truncated before
	the last format character [-Werror=format-truncation=]
    snprintf(status, sizeof(status), "status.%d", i);
                                     ^~~~~~~~~~~
vhci_driver.c:118:4: note: 'snprintf' output between 9 and 18 bytes into
	a destination of size 17
    snprintf(status, sizeof(status), "status.%d", i);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Signed-off-by: Julien BOIBESSOT <julien.boibessot@armadeus.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
get_pipe() routine doesn't validate the input endpoint number
and uses to reference ep_in and ep_out arrays. Invalid endpoint
number can trigger BUG(). Range check the epnum and returning
error instead of calling BUG().

Change caller stub_recv_cmd_submit() to handle the get_pipe()
error return.

Reported-by: Secunia Research <vuln@secunia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Harden CMD_SUBMIT path to handle malicious input that could trigger
large memory allocations. Add checks to validate transfer_buffer_length
and number_of_packets to protect against bad input requesting for
unbounded memory allocations. Validate early in get_pipe() and return
failure.

Reported-by: Secunia Research <vuln@secunia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a client has a USB device attached over IP, the vhci_hcd driver is
locally leaking a socket pointer address via the

/sys/devices/platform/vhci_hcd/status file (world-readable) and in debug
output when "usbip --debug port" is run.

Fix it to not leak. The socket pointer address is not used at the moment
and it was made visible as a convenient way to find IP address from socket
pointer address by looking up /proc/net/{tcp,tcp6}.

As this opens a security hole, the fix replaces socket pointer address with
sockfd.

Reported-by: Secunia Research <vuln@secunia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
stub_send_ret_submit() handles urb with a potential null transfer_buffer,
when it replays a packet with potential malicious data that could contain
a null buffer. Add a check for the condition when actual_length > 0 and
transfer_buffer is null.

Reported-by: Secunia Research <vuln@secunia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Avoid null pointer dereference if some function is walking through the
devs array accessing members of a new virt_dev that is mid allocation.

Add the virt_dev to xhci->devs[i] _after_ the virt_device and all its
members are properly allocated.

issue found by KASAN: null-ptr-deref in xhci_find_slot_id_by_port

"Quick analysis suggests that xhci_alloc_virt_device() is not mutex
protected. If so, there is a time frame where xhci->devs[slot_id] is set
but not fully initialized. Specifically, xhci->devs[i]->udev can be NULL."

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For MTK's xHCI 1.0 or latter, TD size is the number of max
packet sized packets remaining in the TD, not including
this TRB (following spec).

For MTK's xHCI 0.96 and older, TD size is the number of max
packet sized packets remaining in the TD, including this TRB
(not following spec).

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We were never releasing the initial fence reference that is obtained
through dma_fence_init.

Link: anholt/linux#122
Fixes: cdec4d3 ("drm/vc4: Expose dma-buf fences for V3D rendering.")
Signed-off-by: Stefan Schake <stschake@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1512236444-301-1-git-send-email-stschake@gmail.com
These duplicate includes have been found with scripts/checkincludes.pl but
they have been removed manually to avoid removing false positives.

Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit bd44ca3 ]

Currently the dma debugging code can end up indirectly calling printk
under the radix_lock. This happens when a radix tree node allocation
fails.

This is a problem because the printk code, when used together with
netconsole, can end up inside the dma debugging code while trying to
transmit a message over netcons.

This creates the possibility of either a circular deadlock on the same
CPU, with that CPU trying to grab the radix_lock twice, or an ABBA
deadlock between different CPUs, where one CPU grabs the console lock
first and then waits for the radix_lock, while the other CPU is holding
the radix_lock and is waiting for the console lock.

The trace captured by lockdep is of the ABBA variant.

-> #2 (&dma_entry_hash[i].lock){-.-.}-{2:2}:
                  _raw_spin_lock_irqsave+0x5a/0x90
                  debug_dma_map_page+0x79/0x180
                  dma_map_page_attrs+0x1d2/0x2f0
                  bnxt_start_xmit+0x8c6/0x1540
                  netpoll_start_xmit+0x13f/0x180
                  netpoll_send_skb+0x20d/0x320
                  netpoll_send_udp+0x453/0x4a0
                  write_ext_msg+0x1b9/0x460
                  console_flush_all+0x2ff/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  devkmsg_emit+0x5a/0x80
                  devkmsg_write+0xfd/0x180
                  do_iter_readv_writev+0x164/0x1b0
                  vfs_writev+0xf9/0x2b0
                  do_writev+0x6d/0x110
                  do_syscall_64+0x80/0x150
                  entry_SYSCALL_64_after_hwframe+0x4b/0x53

-> #0 (console_owner){-.-.}-{0:0}:
                  __lock_acquire+0x15d1/0x31a0
                  lock_acquire+0xe8/0x290
                  console_flush_all+0x2ea/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  _printk+0x59/0x80
                  warn_alloc+0x122/0x1b0
                  __alloc_pages_slowpath+0x1101/0x1120
                  __alloc_pages+0x1eb/0x2c0
                  alloc_slab_page+0x5f/0x150
                  new_slab+0x2dc/0x4e0
                  ___slab_alloc+0xdcb/0x1390
                  kmem_cache_alloc+0x23d/0x360
                  radix_tree_node_alloc+0x3c/0xf0
                  radix_tree_insert+0xf5/0x230
                  add_dma_entry+0xe9/0x360
                  dma_map_page_attrs+0x1d2/0x2f0
                  __bnxt_alloc_rx_frag+0x147/0x180
                  bnxt_alloc_rx_data+0x79/0x160
                  bnxt_rx_skb+0x29/0xc0
                  bnxt_rx_pkt+0xe22/0x1570
                  __bnxt_poll_work+0x101/0x390
                  bnxt_poll+0x7e/0x320
                  __napi_poll+0x29/0x160
                  net_rx_action+0x1e0/0x3e0
                  handle_softirqs+0x190/0x510
                  run_ksoftirqd+0x4e/0x90
                  smpboot_thread_fn+0x1a8/0x270
                  kthread+0x102/0x120
                  ret_from_fork+0x2f/0x40
                  ret_from_fork_asm+0x11/0x20

This bug is more likely than it seems, because when one CPU has run out
of memory, chances are the other has too.

The good news is, this bug is hidden behind the CONFIG_DMA_API_DEBUG, so
not many users are likely to trigger it.

Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Konstantin Ovsepian <ovs@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit 3e7917c ]

linkwatch_event() grabs possibly very contended RTNL mutex.

system_wq is not suitable for such work.

Inspired by many noisy syzbot reports.

3 locks held by kworker/0:7/5266:
 #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3206 [inline]
 #0: ffff888015480948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x90a/0x1830 kernel/workqueue.c:3312
 #1: ffffc90003f6fd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3207 [inline]
 , at: process_scheduled_works+0x945/0x1830 kernel/workqueue.c:3312
 #2: ffffffff8fa6f208 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:276

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 1da177e ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20240805085821.1616528-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit 86a41ea ]

When l2tp tunnels use a socket provided by userspace, we can hit
lockdep splats like the below when data is transmitted through another
(unrelated) userspace socket which then gets routed over l2tp.

This issue was previously discussed here:
https://lore.kernel.org/netdev/87sfialu2n.fsf@cloudflare.com/

The solution is to have lockdep treat socket locks of l2tp tunnel
sockets separately than those of standard INET sockets. To do so, use
a different lockdep subclass where lock nesting is possible.

  ============================================
  WARNING: possible recursive locking detected
  6.10.0+ #34 Not tainted
  --------------------------------------------
  iperf3/771 is trying to acquire lock:
  ffff8881027601d8 (slock-AF_INET/1){+.-.}-{2:2}, at: l2tp_xmit_skb+0x243/0x9d0

  but task is already holding lock:
  ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(slock-AF_INET/1);
    lock(slock-AF_INET/1);

   *** DEADLOCK ***

   May be due to missing lock nesting notation

  10 locks held by iperf3/771:
   #0: ffff888102650258 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_sendmsg+0x1a/0x40
   #1: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0
   #2: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130
   #3: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x28b/0x9f0
   #4: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0xf9/0x260
   #5: ffff888102650d98 (slock-AF_INET/1){+.-.}-{2:2}, at: tcp_v4_rcv+0x1848/0x1e10
   #6: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x4b/0xbc0
   #7: ffffffff822ac220 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x17a/0x1130
   #8: ffffffff822ac1e0 (rcu_read_lock_bh){....}-{1:2}, at: __dev_queue_xmit+0xcc/0x1450
   #9: ffff888101f33258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#2){+...}-{2:2}, at: __dev_queue_xmit+0x513/0x1450

  stack backtrace:
  CPU: 2 UID: 0 PID: 771 Comm: iperf3 Not tainted 6.10.0+ #34
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
  Call Trace:
   <IRQ>
   dump_stack_lvl+0x69/0xa0
   dump_stack+0xc/0x20
   __lock_acquire+0x135d/0x2600
   ? srso_alias_return_thunk+0x5/0xfbef5
   lock_acquire+0xc4/0x2a0
   ? l2tp_xmit_skb+0x243/0x9d0
   ? __skb_checksum+0xa3/0x540
   _raw_spin_lock_nested+0x35/0x50
   ? l2tp_xmit_skb+0x243/0x9d0
   l2tp_xmit_skb+0x243/0x9d0
   l2tp_eth_dev_xmit+0x3c/0xc0
   dev_hard_start_xmit+0x11e/0x420
   sch_direct_xmit+0xc3/0x640
   __dev_queue_xmit+0x61c/0x1450
   ? ip_finish_output2+0xf4c/0x1130
   ip_finish_output2+0x6b6/0x1130
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? __ip_finish_output+0x217/0x380
   ? srso_alias_return_thunk+0x5/0xfbef5
   __ip_finish_output+0x217/0x380
   ip_output+0x99/0x120
   __ip_queue_xmit+0xae4/0xbc0
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? tcp_options_write.constprop.0+0xcb/0x3e0
   ip_queue_xmit+0x34/0x40
   __tcp_transmit_skb+0x1625/0x1890
   __tcp_send_ack+0x1b8/0x340
   tcp_send_ack+0x23/0x30
   __tcp_ack_snd_check+0xa8/0x530
   ? srso_alias_return_thunk+0x5/0xfbef5
   tcp_rcv_established+0x412/0xd70
   tcp_v4_do_rcv+0x299/0x420
   tcp_v4_rcv+0x1991/0x1e10
   ip_protocol_deliver_rcu+0x50/0x220
   ip_local_deliver_finish+0x158/0x260
   ip_local_deliver+0xc8/0xe0
   ip_rcv+0xe5/0x1d0
   ? __pfx_ip_rcv+0x10/0x10
   __netif_receive_skb_one_core+0xce/0xe0
   ? process_backlog+0x28b/0x9f0
   __netif_receive_skb+0x34/0xd0
   ? process_backlog+0x28b/0x9f0
   process_backlog+0x2cb/0x9f0
   __napi_poll.constprop.0+0x61/0x280
   net_rx_action+0x332/0x670
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? find_held_lock+0x2b/0x80
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? srso_alias_return_thunk+0x5/0xfbef5
   handle_softirqs+0xda/0x480
   ? __dev_queue_xmit+0xa2c/0x1450
   do_softirq+0xa1/0xd0
   </IRQ>
   <TASK>
   __local_bh_enable_ip+0xc8/0xe0
   ? __dev_queue_xmit+0xa2c/0x1450
   __dev_queue_xmit+0xa48/0x1450
   ? ip_finish_output2+0xf4c/0x1130
   ip_finish_output2+0x6b6/0x1130
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? __ip_finish_output+0x217/0x380
   ? srso_alias_return_thunk+0x5/0xfbef5
   __ip_finish_output+0x217/0x380
   ip_output+0x99/0x120
   __ip_queue_xmit+0xae4/0xbc0
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? tcp_options_write.constprop.0+0xcb/0x3e0
   ip_queue_xmit+0x34/0x40
   __tcp_transmit_skb+0x1625/0x1890
   tcp_write_xmit+0x766/0x2fb0
   ? __entry_text_end+0x102ba9/0x102bad
   ? srso_alias_return_thunk+0x5/0xfbef5
   ? __might_fault+0x74/0xc0
   ? srso_alias_return_thunk+0x5/0xfbef5
   __tcp_push_pending_frames+0x56/0x190
   tcp_push+0x117/0x310
   tcp_sendmsg_locked+0x14c1/0x1740
   tcp_sendmsg+0x28/0x40
   inet_sendmsg+0x5d/0x90
   sock_write_iter+0x242/0x2b0
   vfs_write+0x68d/0x800
   ? __pfx_sock_write_iter+0x10/0x10
   ksys_write+0xc8/0xf0
   __x64_sys_write+0x3d/0x50
   x64_sys_call+0xfaf/0x1f50
   do_syscall_64+0x6d/0x140
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
  RIP: 0033:0x7f4d143af992
  Code: c3 8b 07 85 c0 75 24 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> e9 01 cc ff ff 41 54 b8 02 00 00 0
  RSP: 002b:00007ffd65032058 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
  RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f4d143af992
  RDX: 0000000000000025 RSI: 00007f4d143f3bcc RDI: 0000000000000005
  RBP: 00007f4d143f2b28 R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4d143f3bcc
  R13: 0000000000000005 R14: 0000000000000000 R15: 00007ffd650323f0
   </TASK>

Fixes: 0b2c597 ("l2tp: close all race conditions in l2tp_tunnel_register()")
Suggested-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+6acef9e0a4d1f46c83d4@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=6acef9e0a4d1f46c83d4
CC: gnault@redhat.com
CC: cong.wang@bytedance.com
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Link: https://patch.msgid.link/20240806160626.1248317-1-jchapman@katalix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
…pinlock_t'

commit f872d4a upstream.

This lock is acquired under irq_desc::lock with interrupts disabled.

When PREEMPT_RT is enabled, 'spinlock_t' becomes preemptible, which results
in invalid lock acquire context;

  [ BUG: Invalid wait context ]
  swapper/0/1 is trying to lock:
  ffff0000008fed30 (&ctl->lock){....}-{3:3}, at: meson_gpio_irq_update_bits0
  other info that might help us debug this:
  context-{5:5}
  3 locks held by swapper/0/1:
   #0: ffff0000003cd0f8 (&dev->mutex){....}-{4:4}, at: __driver_attach+0x90c
   #1: ffff000004714650 (&desc->request_mutex){+.+.}-{4:4}, at: __setup_irq0
   #2: ffff0000047144c8 (&irq_desc_lock_class){-.-.}-{2:2}, at: __setup_irq0
  stack backtrace:
  CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.9.9-sdkernel #1
  Call trace:
   _raw_spin_lock_irqsave+0x60/0x88
   meson_gpio_irq_update_bits+0x34/0x70
   meson8_gpio_irq_set_type+0x78/0xc4
   meson_gpio_irq_set_type+0x30/0x60
   __irq_set_trigger+0x60/0x180
   __setup_irq+0x30c/0x6e0
   request_threaded_irq+0xec/0x1a4

Fixes: 215f4cc ("irqchip/meson: Add support for gpio interrupt controller")
Signed-off-by: Arseniy Krasnov <avkrasnov@salutedevices.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20240729131850.3015508-1-avkrasnov@salutedevices.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit b313a8c ]

Lockdep reported a warning in Linux version 6.6:

[  414.344659] ================================
[  414.345155] WARNING: inconsistent lock state
[  414.345658] 6.6.0-07439-gba2303cacfda #6 Not tainted
[  414.346221] --------------------------------
[  414.346712] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[  414.347545] kworker/u10:3/1152 [HC0[0]:SC0[0]:HE0:SE1] takes:
[  414.349245] ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.351204] {IN-SOFTIRQ-W} state was registered at:
[  414.351751]   lock_acquire+0x18d/0x460
[  414.352218]   _raw_spin_lock_irqsave+0x39/0x60
[  414.352769]   __wake_up_common_lock+0x22/0x60
[  414.353289]   sbitmap_queue_wake_up+0x375/0x4f0
[  414.353829]   sbitmap_queue_clear+0xdd/0x270
[  414.354338]   blk_mq_put_tag+0xdf/0x170
[  414.354807]   __blk_mq_free_request+0x381/0x4d0
[  414.355335]   blk_mq_free_request+0x28b/0x3e0
[  414.355847]   __blk_mq_end_request+0x242/0xc30
[  414.356367]   scsi_end_request+0x2c1/0x830
[  414.345155] WARNING: inconsistent lock state
[  414.345658] 6.6.0-07439-gba2303cacfda #6 Not tainted
[  414.346221] --------------------------------
[  414.346712] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[  414.347545] kworker/u10:3/1152 [HC0[0]:SC0[0]:HE0:SE1] takes:
[  414.349245] ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.351204] {IN-SOFTIRQ-W} state was registered at:
[  414.351751]   lock_acquire+0x18d/0x460
[  414.352218]   _raw_spin_lock_irqsave+0x39/0x60
[  414.352769]   __wake_up_common_lock+0x22/0x60
[  414.353289]   sbitmap_queue_wake_up+0x375/0x4f0
[  414.353829]   sbitmap_queue_clear+0xdd/0x270
[  414.354338]   blk_mq_put_tag+0xdf/0x170
[  414.354807]   __blk_mq_free_request+0x381/0x4d0
[  414.355335]   blk_mq_free_request+0x28b/0x3e0
[  414.355847]   __blk_mq_end_request+0x242/0xc30
[  414.356367]   scsi_end_request+0x2c1/0x830
[  414.356863]   scsi_io_completion+0x177/0x1610
[  414.357379]   scsi_complete+0x12f/0x260
[  414.357856]   blk_complete_reqs+0xba/0xf0
[  414.358338]   __do_softirq+0x1b0/0x7a2
[  414.358796]   irq_exit_rcu+0x14b/0x1a0
[  414.359262]   sysvec_call_function_single+0xaf/0xc0
[  414.359828]   asm_sysvec_call_function_single+0x1a/0x20
[  414.360426]   default_idle+0x1e/0x30
[  414.360873]   default_idle_call+0x9b/0x1f0
[  414.361390]   do_idle+0x2d2/0x3e0
[  414.361819]   cpu_startup_entry+0x55/0x60
[  414.362314]   start_secondary+0x235/0x2b0
[  414.362809]   secondary_startup_64_no_verify+0x18f/0x19b
[  414.363413] irq event stamp: 428794
[  414.363825] hardirqs last  enabled at (428793): [<ffffffff816bfd1c>] ktime_get+0x1dc/0x200
[  414.364694] hardirqs last disabled at (428794): [<ffffffff85470177>] _raw_spin_lock_irq+0x47/0x50
[  414.365629] softirqs last  enabled at (428444): [<ffffffff85474780>] __do_softirq+0x540/0x7a2
[  414.366522] softirqs last disabled at (428419): [<ffffffff813f65ab>] irq_exit_rcu+0x14b/0x1a0
[  414.367425]
               other info that might help us debug this:
[  414.368194]  Possible unsafe locking scenario:
[  414.368900]        CPU0
[  414.369225]        ----
[  414.369548]   lock(&sbq->ws[i].wait);
[  414.370000]   <Interrupt>
[  414.370342]     lock(&sbq->ws[i].wait);
[  414.370802]
                *** DEADLOCK ***
[  414.371569] 5 locks held by kworker/u10:3/1152:
[  414.372088]  #0: ffff88810130e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x357/0x13f0
[  414.373180]  #1: ffff88810201fdb8 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x3a3/0x13f0
[  414.374384]  #2: ffffffff86ffbdc0 (rcu_read_lock){....}-{1:2}, at: blk_mq_run_hw_queue+0x637/0xa00
[  414.375342]  #3: ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.376377]  #4: ffff888106205a08 (&hctx->dispatch_wait_lock){+.-.}-{2:2}, at: blk_mq_dispatch_rq_list+0x1337/0x1ee0
[  414.378607]
               stack backtrace:
[  414.379177] CPU: 0 PID: 1152 Comm: kworker/u10:3 Not tainted 6.6.0-07439-gba2303cacfda #6
[  414.380032] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  414.381177] Workqueue: writeback wb_workfn (flush-253:0)
[  414.381805] Call Trace:
[  414.382136]  <TASK>
[  414.382429]  dump_stack_lvl+0x91/0xf0
[  414.382884]  mark_lock_irq+0xb3b/0x1260
[  414.383367]  ? __pfx_mark_lock_irq+0x10/0x10
[  414.383889]  ? stack_trace_save+0x8e/0xc0
[  414.384373]  ? __pfx_stack_trace_save+0x10/0x10
[  414.384903]  ? graph_lock+0xcf/0x410
[  414.385350]  ? save_trace+0x3d/0xc70
[  414.385808]  mark_lock.part.20+0x56d/0xa90
[  414.386317]  mark_held_locks+0xb0/0x110
[  414.386791]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  414.387320]  lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.387901]  ? _raw_spin_unlock_irq+0x28/0x50
[  414.388422]  trace_hardirqs_on+0x58/0x100
[  414.388917]  _raw_spin_unlock_irq+0x28/0x50
[  414.389422]  __blk_mq_tag_busy+0x1d6/0x2a0
[  414.389920]  __blk_mq_get_driver_tag+0x761/0x9f0
[  414.390899]  blk_mq_dispatch_rq_list+0x1780/0x1ee0
[  414.391473]  ? __pfx_blk_mq_dispatch_rq_list+0x10/0x10
[  414.392070]  ? sbitmap_get+0x2b8/0x450
[  414.392533]  ? __blk_mq_get_driver_tag+0x210/0x9f0
[  414.393095]  __blk_mq_sched_dispatch_requests+0xd99/0x1690
[  414.393730]  ? elv_attempt_insert_merge+0x1b1/0x420
[  414.394302]  ? __pfx___blk_mq_sched_dispatch_requests+0x10/0x10
[  414.394970]  ? lock_acquire+0x18d/0x460
[  414.395456]  ? blk_mq_run_hw_queue+0x637/0xa00
[  414.395986]  ? __pfx_lock_acquire+0x10/0x10
[  414.396499]  blk_mq_sched_dispatch_requests+0x109/0x190
[  414.397100]  blk_mq_run_hw_queue+0x66e/0xa00
[  414.397616]  blk_mq_flush_plug_list.part.17+0x614/0x2030
[  414.398244]  ? __pfx_blk_mq_flush_plug_list.part.17+0x10/0x10
[  414.398897]  ? writeback_sb_inodes+0x241/0xcc0
[  414.399429]  blk_mq_flush_plug_list+0x65/0x80
[  414.399957]  __blk_flush_plug+0x2f1/0x530
[  414.400458]  ? __pfx___blk_flush_plug+0x10/0x10
[  414.400999]  blk_finish_plug+0x59/0xa0
[  414.401467]  wb_writeback+0x7cc/0x920
[  414.401935]  ? __pfx_wb_writeback+0x10/0x10
[  414.402442]  ? mark_held_locks+0xb0/0x110
[  414.402931]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  414.403462]  ? lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.404062]  wb_workfn+0x2b3/0xcf0
[  414.404500]  ? __pfx_wb_workfn+0x10/0x10
[  414.404989]  process_scheduled_works+0x432/0x13f0
[  414.405546]  ? __pfx_process_scheduled_works+0x10/0x10
[  414.406139]  ? do_raw_spin_lock+0x101/0x2a0
[  414.406641]  ? assign_work+0x19b/0x240
[  414.407106]  ? lock_is_held_type+0x9d/0x110
[  414.407604]  worker_thread+0x6f2/0x1160
[  414.408075]  ? __kthread_parkme+0x62/0x210
[  414.408572]  ? lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.409168]  ? __kthread_parkme+0x13c/0x210
[  414.409678]  ? __pfx_worker_thread+0x10/0x10
[  414.410191]  kthread+0x33c/0x440
[  414.410602]  ? __pfx_kthread+0x10/0x10
[  414.411068]  ret_from_fork+0x4d/0x80
[  414.411526]  ? __pfx_kthread+0x10/0x10
[  414.411993]  ret_from_fork_asm+0x1b/0x30
[  414.412489]  </TASK>

When interrupt is turned on while a lock holding by spin_lock_irq it
throws a warning because of potential deadlock.

blk_mq_prep_dispatch_rq
 blk_mq_get_driver_tag
  __blk_mq_get_driver_tag
   __blk_mq_alloc_driver_tag
    blk_mq_tag_busy -> tag is already busy
    // failed to get driver tag
 blk_mq_mark_tag_wait
  spin_lock_irq(&wq->lock) -> lock A (&sbq->ws[i].wait)
  __add_wait_queue(wq, wait) -> wait queue active
  blk_mq_get_driver_tag
  __blk_mq_tag_busy
-> 1) tag must be idle, which means there can't be inflight IO
   spin_lock_irq(&tags->lock) -> lock B (hctx->tags)
   spin_unlock_irq(&tags->lock) -> unlock B, turn on interrupt accidentally
-> 2) context must be preempt by IO interrupt to trigger deadlock.

As shown above, the deadlock is not possible in theory, but the warning
still need to be fixed.

Fix it by using spin_lock_irqsave to get lockB instead of spin_lock_irq.

Fixes: 4f1731d ("blk-mq: fix potential io hang by wrong 'wake_batch'")
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240815024736.2040971-1-lilingfeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit bd44ca3 ]

Currently the dma debugging code can end up indirectly calling printk
under the radix_lock. This happens when a radix tree node allocation
fails.

This is a problem because the printk code, when used together with
netconsole, can end up inside the dma debugging code while trying to
transmit a message over netcons.

This creates the possibility of either a circular deadlock on the same
CPU, with that CPU trying to grab the radix_lock twice, or an ABBA
deadlock between different CPUs, where one CPU grabs the console lock
first and then waits for the radix_lock, while the other CPU is holding
the radix_lock and is waiting for the console lock.

The trace captured by lockdep is of the ABBA variant.

-> #2 (&dma_entry_hash[i].lock){-.-.}-{2:2}:
                  _raw_spin_lock_irqsave+0x5a/0x90
                  debug_dma_map_page+0x79/0x180
                  dma_map_page_attrs+0x1d2/0x2f0
                  bnxt_start_xmit+0x8c6/0x1540
                  netpoll_start_xmit+0x13f/0x180
                  netpoll_send_skb+0x20d/0x320
                  netpoll_send_udp+0x453/0x4a0
                  write_ext_msg+0x1b9/0x460
                  console_flush_all+0x2ff/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  devkmsg_emit+0x5a/0x80
                  devkmsg_write+0xfd/0x180
                  do_iter_readv_writev+0x164/0x1b0
                  vfs_writev+0xf9/0x2b0
                  do_writev+0x6d/0x110
                  do_syscall_64+0x80/0x150
                  entry_SYSCALL_64_after_hwframe+0x4b/0x53

-> #0 (console_owner){-.-.}-{0:0}:
                  __lock_acquire+0x15d1/0x31a0
                  lock_acquire+0xe8/0x290
                  console_flush_all+0x2ea/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  _printk+0x59/0x80
                  warn_alloc+0x122/0x1b0
                  __alloc_pages_slowpath+0x1101/0x1120
                  __alloc_pages+0x1eb/0x2c0
                  alloc_slab_page+0x5f/0x150
                  new_slab+0x2dc/0x4e0
                  ___slab_alloc+0xdcb/0x1390
                  kmem_cache_alloc+0x23d/0x360
                  radix_tree_node_alloc+0x3c/0xf0
                  radix_tree_insert+0xf5/0x230
                  add_dma_entry+0xe9/0x360
                  dma_map_page_attrs+0x1d2/0x2f0
                  __bnxt_alloc_rx_frag+0x147/0x180
                  bnxt_alloc_rx_data+0x79/0x160
                  bnxt_rx_skb+0x29/0xc0
                  bnxt_rx_pkt+0xe22/0x1570
                  __bnxt_poll_work+0x101/0x390
                  bnxt_poll+0x7e/0x320
                  __napi_poll+0x29/0x160
                  net_rx_action+0x1e0/0x3e0
                  handle_softirqs+0x190/0x510
                  run_ksoftirqd+0x4e/0x90
                  smpboot_thread_fn+0x1a8/0x270
                  kthread+0x102/0x120
                  ret_from_fork+0x2f/0x40
                  ret_from_fork_asm+0x11/0x20

This bug is more likely than it seems, because when one CPU has run out
of memory, chances are the other has too.

The good news is, this bug is hidden behind the CONFIG_DMA_API_DEBUG, so
not many users are likely to trigger it.

Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Konstantin Ovsepian <ovs@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit 56f4526 ]

This timer HW supports 8, 16 and 32-bit timer widths. This
driver currently uses a u32 to store the max possible value
of the timer. However, statements perform addition of 2 in
xilinx_pwm_apply() when calculating the period_cycles and
duty_cycles values. Since priv->max is a u32, this will
result in an overflow to 1 which will not only be incorrect
but fail on range comparison. This results in making it
impossible to set the PWM in this timer mode.

There are two obvious solutions to the current problem:
1. Cast each instance where overflow occurs to u64.
2. Change priv->max from a u32 to a u64.

Solution #1 requires more code modifications, and leaves
opportunity to introduce similar overflows if other math
statements are added in the future. These may also go
undetected if running in non 32-bit timer modes.

Solution #2 is the much smaller and cleaner approach and
thus the chosen method in this patch.

This was tested on a Zynq UltraScale+ with multiple
instances of the PWM IP.

Signed-off-by: Ken Sloat <ksloat@designlinxhs.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/SJ0P222MB0107490C5371B848EF04351CA1E19@SJ0P222MB0107.NAMP222.PROD.OUTLOOK.COM
Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
…ct_cfm

commit 9a8ec9e upstream.

This attempts to fix the following trace:

======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-g0b93eeba4454 #4703 Not tainted
------------------------------------------------------
kworker/u3:0/46 is trying to acquire lock:
ffff888001fd9130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
sco_connect_cfm+0x118/0x4a0

but task is already holding lock:
ffffffff831e3340 (hci_cb_list_lock){+.+.}-{3:3}, at:
hci_sync_conn_complete_evt+0x1ad/0x3d0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock+0x13b/0xcc0
       hci_sync_conn_complete_evt+0x1ad/0x3d0
       hci_event_packet+0x55c/0x7c0
       hci_rx_work+0x34c/0xa00
       process_one_work+0x575/0x910
       worker_thread+0x89/0x6f0
       kthread+0x14e/0x180
       ret_from_fork+0x2b/0x50

-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock+0x13b/0xcc0
       sco_sock_connect+0xfc/0x630
       __sys_connect+0x197/0x1b0
       __x64_sys_connect+0x37/0x50
       do_syscall_64+0x42/0x90
       entry_SYSCALL_64_after_hwframe+0x70/0xda

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       __lock_acquire+0x18cc/0x3740
       lock_acquire+0x151/0x3a0
       lock_sock_nested+0x32/0x80
       sco_connect_cfm+0x118/0x4a0
       hci_sync_conn_complete_evt+0x1e6/0x3d0
       hci_event_packet+0x55c/0x7c0
       hci_rx_work+0x34c/0xa00
       process_one_work+0x575/0x910
       worker_thread+0x89/0x6f0
       kthread+0x14e/0x180
       ret_from_fork+0x2b/0x50

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hci_cb_list_lock);
                               lock(&hdev->lock);
                               lock(hci_cb_list_lock);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

4 locks held by kworker/u3:0/46:
 #0: ffff8880028d1130 ((wq_completion)hci0#2){+.+.}-{0:0}, at:
 process_one_work+0x4c0/0x910
 #1: ffff8880013dfde0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0},
 at: process_one_work+0x4c0/0x910
 #2: ffff8880025d8070 (&hdev->lock){+.+.}-{3:3}, at:
 hci_sync_conn_complete_evt+0xa6/0x3d0
 #3: ffffffffb79e3340 (hci_cb_list_lock){+.+.}-{3:3}, at:
 hci_sync_conn_complete_evt+0x1ad/0x3d0

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit b313a8c ]

Lockdep reported a warning in Linux version 6.6:

[  414.344659] ================================
[  414.345155] WARNING: inconsistent lock state
[  414.345658] 6.6.0-07439-gba2303cacfda #6 Not tainted
[  414.346221] --------------------------------
[  414.346712] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[  414.347545] kworker/u10:3/1152 [HC0[0]:SC0[0]:HE0:SE1] takes:
[  414.349245] ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.351204] {IN-SOFTIRQ-W} state was registered at:
[  414.351751]   lock_acquire+0x18d/0x460
[  414.352218]   _raw_spin_lock_irqsave+0x39/0x60
[  414.352769]   __wake_up_common_lock+0x22/0x60
[  414.353289]   sbitmap_queue_wake_up+0x375/0x4f0
[  414.353829]   sbitmap_queue_clear+0xdd/0x270
[  414.354338]   blk_mq_put_tag+0xdf/0x170
[  414.354807]   __blk_mq_free_request+0x381/0x4d0
[  414.355335]   blk_mq_free_request+0x28b/0x3e0
[  414.355847]   __blk_mq_end_request+0x242/0xc30
[  414.356367]   scsi_end_request+0x2c1/0x830
[  414.345155] WARNING: inconsistent lock state
[  414.345658] 6.6.0-07439-gba2303cacfda #6 Not tainted
[  414.346221] --------------------------------
[  414.346712] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[  414.347545] kworker/u10:3/1152 [HC0[0]:SC0[0]:HE0:SE1] takes:
[  414.349245] ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.351204] {IN-SOFTIRQ-W} state was registered at:
[  414.351751]   lock_acquire+0x18d/0x460
[  414.352218]   _raw_spin_lock_irqsave+0x39/0x60
[  414.352769]   __wake_up_common_lock+0x22/0x60
[  414.353289]   sbitmap_queue_wake_up+0x375/0x4f0
[  414.353829]   sbitmap_queue_clear+0xdd/0x270
[  414.354338]   blk_mq_put_tag+0xdf/0x170
[  414.354807]   __blk_mq_free_request+0x381/0x4d0
[  414.355335]   blk_mq_free_request+0x28b/0x3e0
[  414.355847]   __blk_mq_end_request+0x242/0xc30
[  414.356367]   scsi_end_request+0x2c1/0x830
[  414.356863]   scsi_io_completion+0x177/0x1610
[  414.357379]   scsi_complete+0x12f/0x260
[  414.357856]   blk_complete_reqs+0xba/0xf0
[  414.358338]   __do_softirq+0x1b0/0x7a2
[  414.358796]   irq_exit_rcu+0x14b/0x1a0
[  414.359262]   sysvec_call_function_single+0xaf/0xc0
[  414.359828]   asm_sysvec_call_function_single+0x1a/0x20
[  414.360426]   default_idle+0x1e/0x30
[  414.360873]   default_idle_call+0x9b/0x1f0
[  414.361390]   do_idle+0x2d2/0x3e0
[  414.361819]   cpu_startup_entry+0x55/0x60
[  414.362314]   start_secondary+0x235/0x2b0
[  414.362809]   secondary_startup_64_no_verify+0x18f/0x19b
[  414.363413] irq event stamp: 428794
[  414.363825] hardirqs last  enabled at (428793): [<ffffffff816bfd1c>] ktime_get+0x1dc/0x200
[  414.364694] hardirqs last disabled at (428794): [<ffffffff85470177>] _raw_spin_lock_irq+0x47/0x50
[  414.365629] softirqs last  enabled at (428444): [<ffffffff85474780>] __do_softirq+0x540/0x7a2
[  414.366522] softirqs last disabled at (428419): [<ffffffff813f65ab>] irq_exit_rcu+0x14b/0x1a0
[  414.367425]
               other info that might help us debug this:
[  414.368194]  Possible unsafe locking scenario:
[  414.368900]        CPU0
[  414.369225]        ----
[  414.369548]   lock(&sbq->ws[i].wait);
[  414.370000]   <Interrupt>
[  414.370342]     lock(&sbq->ws[i].wait);
[  414.370802]
                *** DEADLOCK ***
[  414.371569] 5 locks held by kworker/u10:3/1152:
[  414.372088]  #0: ffff88810130e938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x357/0x13f0
[  414.373180]  #1: ffff88810201fdb8 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x3a3/0x13f0
[  414.374384]  #2: ffffffff86ffbdc0 (rcu_read_lock){....}-{1:2}, at: blk_mq_run_hw_queue+0x637/0xa00
[  414.375342]  #3: ffff88810edd1098 (&sbq->ws[i].wait){+.?.}-{2:2}, at: blk_mq_dispatch_rq_list+0x131c/0x1ee0
[  414.376377]  #4: ffff888106205a08 (&hctx->dispatch_wait_lock){+.-.}-{2:2}, at: blk_mq_dispatch_rq_list+0x1337/0x1ee0
[  414.378607]
               stack backtrace:
[  414.379177] CPU: 0 PID: 1152 Comm: kworker/u10:3 Not tainted 6.6.0-07439-gba2303cacfda #6
[  414.380032] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[  414.381177] Workqueue: writeback wb_workfn (flush-253:0)
[  414.381805] Call Trace:
[  414.382136]  <TASK>
[  414.382429]  dump_stack_lvl+0x91/0xf0
[  414.382884]  mark_lock_irq+0xb3b/0x1260
[  414.383367]  ? __pfx_mark_lock_irq+0x10/0x10
[  414.383889]  ? stack_trace_save+0x8e/0xc0
[  414.384373]  ? __pfx_stack_trace_save+0x10/0x10
[  414.384903]  ? graph_lock+0xcf/0x410
[  414.385350]  ? save_trace+0x3d/0xc70
[  414.385808]  mark_lock.part.20+0x56d/0xa90
[  414.386317]  mark_held_locks+0xb0/0x110
[  414.386791]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  414.387320]  lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.387901]  ? _raw_spin_unlock_irq+0x28/0x50
[  414.388422]  trace_hardirqs_on+0x58/0x100
[  414.388917]  _raw_spin_unlock_irq+0x28/0x50
[  414.389422]  __blk_mq_tag_busy+0x1d6/0x2a0
[  414.389920]  __blk_mq_get_driver_tag+0x761/0x9f0
[  414.390899]  blk_mq_dispatch_rq_list+0x1780/0x1ee0
[  414.391473]  ? __pfx_blk_mq_dispatch_rq_list+0x10/0x10
[  414.392070]  ? sbitmap_get+0x2b8/0x450
[  414.392533]  ? __blk_mq_get_driver_tag+0x210/0x9f0
[  414.393095]  __blk_mq_sched_dispatch_requests+0xd99/0x1690
[  414.393730]  ? elv_attempt_insert_merge+0x1b1/0x420
[  414.394302]  ? __pfx___blk_mq_sched_dispatch_requests+0x10/0x10
[  414.394970]  ? lock_acquire+0x18d/0x460
[  414.395456]  ? blk_mq_run_hw_queue+0x637/0xa00
[  414.395986]  ? __pfx_lock_acquire+0x10/0x10
[  414.396499]  blk_mq_sched_dispatch_requests+0x109/0x190
[  414.397100]  blk_mq_run_hw_queue+0x66e/0xa00
[  414.397616]  blk_mq_flush_plug_list.part.17+0x614/0x2030
[  414.398244]  ? __pfx_blk_mq_flush_plug_list.part.17+0x10/0x10
[  414.398897]  ? writeback_sb_inodes+0x241/0xcc0
[  414.399429]  blk_mq_flush_plug_list+0x65/0x80
[  414.399957]  __blk_flush_plug+0x2f1/0x530
[  414.400458]  ? __pfx___blk_flush_plug+0x10/0x10
[  414.400999]  blk_finish_plug+0x59/0xa0
[  414.401467]  wb_writeback+0x7cc/0x920
[  414.401935]  ? __pfx_wb_writeback+0x10/0x10
[  414.402442]  ? mark_held_locks+0xb0/0x110
[  414.402931]  ? __pfx_do_raw_spin_lock+0x10/0x10
[  414.403462]  ? lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.404062]  wb_workfn+0x2b3/0xcf0
[  414.404500]  ? __pfx_wb_workfn+0x10/0x10
[  414.404989]  process_scheduled_works+0x432/0x13f0
[  414.405546]  ? __pfx_process_scheduled_works+0x10/0x10
[  414.406139]  ? do_raw_spin_lock+0x101/0x2a0
[  414.406641]  ? assign_work+0x19b/0x240
[  414.407106]  ? lock_is_held_type+0x9d/0x110
[  414.407604]  worker_thread+0x6f2/0x1160
[  414.408075]  ? __kthread_parkme+0x62/0x210
[  414.408572]  ? lockdep_hardirqs_on_prepare+0x297/0x3f0
[  414.409168]  ? __kthread_parkme+0x13c/0x210
[  414.409678]  ? __pfx_worker_thread+0x10/0x10
[  414.410191]  kthread+0x33c/0x440
[  414.410602]  ? __pfx_kthread+0x10/0x10
[  414.411068]  ret_from_fork+0x4d/0x80
[  414.411526]  ? __pfx_kthread+0x10/0x10
[  414.411993]  ret_from_fork_asm+0x1b/0x30
[  414.412489]  </TASK>

When interrupt is turned on while a lock holding by spin_lock_irq it
throws a warning because of potential deadlock.

blk_mq_prep_dispatch_rq
 blk_mq_get_driver_tag
  __blk_mq_get_driver_tag
   __blk_mq_alloc_driver_tag
    blk_mq_tag_busy -> tag is already busy
    // failed to get driver tag
 blk_mq_mark_tag_wait
  spin_lock_irq(&wq->lock) -> lock A (&sbq->ws[i].wait)
  __add_wait_queue(wq, wait) -> wait queue active
  blk_mq_get_driver_tag
  __blk_mq_tag_busy
-> 1) tag must be idle, which means there can't be inflight IO
   spin_lock_irq(&tags->lock) -> lock B (hctx->tags)
   spin_unlock_irq(&tags->lock) -> unlock B, turn on interrupt accidentally
-> 2) context must be preempt by IO interrupt to trigger deadlock.

As shown above, the deadlock is not possible in theory, but the warning
still need to be fixed.

Fix it by using spin_lock_irqsave to get lockB instead of spin_lock_irq.

Fixes: 4f1731d ("blk-mq: fix potential io hang by wrong 'wake_batch'")
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240815024736.2040971-1-lilingfeng@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit bd44ca3 ]

Currently the dma debugging code can end up indirectly calling printk
under the radix_lock. This happens when a radix tree node allocation
fails.

This is a problem because the printk code, when used together with
netconsole, can end up inside the dma debugging code while trying to
transmit a message over netcons.

This creates the possibility of either a circular deadlock on the same
CPU, with that CPU trying to grab the radix_lock twice, or an ABBA
deadlock between different CPUs, where one CPU grabs the console lock
first and then waits for the radix_lock, while the other CPU is holding
the radix_lock and is waiting for the console lock.

The trace captured by lockdep is of the ABBA variant.

-> #2 (&dma_entry_hash[i].lock){-.-.}-{2:2}:
                  _raw_spin_lock_irqsave+0x5a/0x90
                  debug_dma_map_page+0x79/0x180
                  dma_map_page_attrs+0x1d2/0x2f0
                  bnxt_start_xmit+0x8c6/0x1540
                  netpoll_start_xmit+0x13f/0x180
                  netpoll_send_skb+0x20d/0x320
                  netpoll_send_udp+0x453/0x4a0
                  write_ext_msg+0x1b9/0x460
                  console_flush_all+0x2ff/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  devkmsg_emit+0x5a/0x80
                  devkmsg_write+0xfd/0x180
                  do_iter_readv_writev+0x164/0x1b0
                  vfs_writev+0xf9/0x2b0
                  do_writev+0x6d/0x110
                  do_syscall_64+0x80/0x150
                  entry_SYSCALL_64_after_hwframe+0x4b/0x53

-> #0 (console_owner){-.-.}-{0:0}:
                  __lock_acquire+0x15d1/0x31a0
                  lock_acquire+0xe8/0x290
                  console_flush_all+0x2ea/0x5a0
                  console_unlock+0x55/0x180
                  vprintk_emit+0x2e3/0x3c0
                  _printk+0x59/0x80
                  warn_alloc+0x122/0x1b0
                  __alloc_pages_slowpath+0x1101/0x1120
                  __alloc_pages+0x1eb/0x2c0
                  alloc_slab_page+0x5f/0x150
                  new_slab+0x2dc/0x4e0
                  ___slab_alloc+0xdcb/0x1390
                  kmem_cache_alloc+0x23d/0x360
                  radix_tree_node_alloc+0x3c/0xf0
                  radix_tree_insert+0xf5/0x230
                  add_dma_entry+0xe9/0x360
                  dma_map_page_attrs+0x1d2/0x2f0
                  __bnxt_alloc_rx_frag+0x147/0x180
                  bnxt_alloc_rx_data+0x79/0x160
                  bnxt_rx_skb+0x29/0xc0
                  bnxt_rx_pkt+0xe22/0x1570
                  __bnxt_poll_work+0x101/0x390
                  bnxt_poll+0x7e/0x320
                  __napi_poll+0x29/0x160
                  net_rx_action+0x1e0/0x3e0
                  handle_softirqs+0x190/0x510
                  run_ksoftirqd+0x4e/0x90
                  smpboot_thread_fn+0x1a8/0x270
                  kthread+0x102/0x120
                  ret_from_fork+0x2f/0x40
                  ret_from_fork_asm+0x11/0x20

This bug is more likely than it seems, because when one CPU has run out
of memory, chances are the other has too.

The good news is, this bug is hidden behind the CONFIG_DMA_API_DEBUG, so
not many users are likely to trigger it.

Signed-off-by: Rik van Riel <riel@surriel.com>
Reported-by: Konstantin Ovsepian <ovs@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit 56f4526 ]

This timer HW supports 8, 16 and 32-bit timer widths. This
driver currently uses a u32 to store the max possible value
of the timer. However, statements perform addition of 2 in
xilinx_pwm_apply() when calculating the period_cycles and
duty_cycles values. Since priv->max is a u32, this will
result in an overflow to 1 which will not only be incorrect
but fail on range comparison. This results in making it
impossible to set the PWM in this timer mode.

There are two obvious solutions to the current problem:
1. Cast each instance where overflow occurs to u64.
2. Change priv->max from a u32 to a u64.

Solution #1 requires more code modifications, and leaves
opportunity to introduce similar overflows if other math
statements are added in the future. These may also go
undetected if running in non 32-bit timer modes.

Solution #2 is the much smaller and cleaner approach and
thus the chosen method in this patch.

This was tested on a Zynq UltraScale+ with multiple
instances of the PWM IP.

Signed-off-by: Ken Sloat <ksloat@designlinxhs.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Sean Anderson <sean.anderson@seco.com>
Link: https://lore.kernel.org/r/SJ0P222MB0107490C5371B848EF04351CA1E19@SJ0P222MB0107.NAMP222.PROD.OUTLOOK.COM
Signed-off-by: Michal Simek <michal.simek@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
commit f9c169b upstream.

If smb2_compound_op() is called with a valid @CFILE and returned
-EINVAL, we need to call cifs_get_writable_path() before retrying it
as the reference of @CFILE was already dropped by previous call.

This fixes the following KASAN splat when running fstests generic/013
against Windows Server 2022:

  CIFS: Attempting to mount //w22-fs0/scratch
  run fstests generic/013 at 2024-09-02 19:48:59
  ==================================================================
  BUG: KASAN: slab-use-after-free in detach_if_pending+0xab/0x200
  Write of size 8 at addr ffff88811f1a3730 by task kworker/3:2/176

  CPU: 3 UID: 0 PID: 176 Comm: kworker/3:2 Not tainted 6.11.0-rc6 #2
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40
  04/01/2014
  Workqueue: cifsoplockd cifs_oplock_break [cifs]
  Call Trace:
   <TASK>
   dump_stack_lvl+0x5d/0x80
   ? detach_if_pending+0xab/0x200
   print_report+0x156/0x4d9
   ? detach_if_pending+0xab/0x200
   ? __virt_addr_valid+0x145/0x300
   ? __phys_addr+0x46/0x90
   ? detach_if_pending+0xab/0x200
   kasan_report+0xda/0x110
   ? detach_if_pending+0xab/0x200
   detach_if_pending+0xab/0x200
   timer_delete+0x96/0xe0
   ? __pfx_timer_delete+0x10/0x10
   ? rcu_is_watching+0x20/0x50
   try_to_grab_pending+0x46/0x3b0
   __cancel_work+0x89/0x1b0
   ? __pfx___cancel_work+0x10/0x10
   ? kasan_save_track+0x14/0x30
   cifs_close_deferred_file+0x110/0x2c0 [cifs]
   ? __pfx_cifs_close_deferred_file+0x10/0x10 [cifs]
   ? __pfx_down_read+0x10/0x10
   cifs_oplock_break+0x4c1/0xa50 [cifs]
   ? __pfx_cifs_oplock_break+0x10/0x10 [cifs]
   ? lock_is_held_type+0x85/0xf0
   ? mark_held_locks+0x1a/0x90
   process_one_work+0x4c6/0x9f0
   ? find_held_lock+0x8a/0xa0
   ? __pfx_process_one_work+0x10/0x10
   ? lock_acquired+0x220/0x550
   ? __list_add_valid_or_report+0x37/0x100
   worker_thread+0x2e4/0x570
   ? __kthread_parkme+0xd1/0xf0
   ? __pfx_worker_thread+0x10/0x10
   kthread+0x17f/0x1c0
   ? kthread+0xda/0x1c0
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x31/0x60
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

  Allocated by task 1118:
   kasan_save_stack+0x30/0x50
   kasan_save_track+0x14/0x30
   __kasan_kmalloc+0xaa/0xb0
   cifs_new_fileinfo+0xc8/0x9d0 [cifs]
   cifs_atomic_open+0x467/0x770 [cifs]
   lookup_open.isra.0+0x665/0x8b0
   path_openat+0x4c3/0x1380
   do_filp_open+0x167/0x270
   do_sys_openat2+0x129/0x160
   __x64_sys_creat+0xad/0xe0
   do_syscall_64+0xbb/0x1d0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  Freed by task 83:
   kasan_save_stack+0x30/0x50
   kasan_save_track+0x14/0x30
   kasan_save_free_info+0x3b/0x70
   poison_slab_object+0xe9/0x160
   __kasan_slab_free+0x32/0x50
   kfree+0xf2/0x300
   process_one_work+0x4c6/0x9f0
   worker_thread+0x2e4/0x570
   kthread+0x17f/0x1c0
   ret_from_fork+0x31/0x60
   ret_from_fork_asm+0x1a/0x30

  Last potentially related work creation:
   kasan_save_stack+0x30/0x50
   __kasan_record_aux_stack+0xad/0xc0
   insert_work+0x29/0xe0
   __queue_work+0x5ea/0x760
   queue_work_on+0x6d/0x90
   _cifsFileInfo_put+0x3f6/0x770 [cifs]
   smb2_compound_op+0x911/0x3940 [cifs]
   smb2_set_path_size+0x228/0x270 [cifs]
   cifs_set_file_size+0x197/0x460 [cifs]
   cifs_setattr+0xd9c/0x14b0 [cifs]
   notify_change+0x4e3/0x740
   do_truncate+0xfa/0x180
   vfs_truncate+0x195/0x200
   __x64_sys_truncate+0x109/0x150
   do_syscall_64+0xbb/0x1d0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: 71f15c9 ("smb: client: retry compound request without reusing lease")
Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
commit d260327 upstream.

Chi Zhiling reported:

  We found a null pointer accessing in tracefs[1], the reason is that the
  variable 'ei_child' is set to LIST_POISON1, that means the list was
  removed in eventfs_remove_rec. so when access the ei_child->is_freed, the
  panic triggered.

  by the way, the following script can reproduce this panic

  loop1 (){
      while true
      do
          echo "p:kp submit_bio" > /sys/kernel/debug/tracing/kprobe_events
          echo "" > /sys/kernel/debug/tracing/kprobe_events
      done
  }
  loop2 (){
      while true
      do
          tree /sys/kernel/debug/tracing/events/kprobes/
      done
  }
  loop1 &
  loop2

  [1]:
  [ 1147.959632][T17331] Unable to handle kernel paging request at virtual address dead000000000150
  [ 1147.968239][T17331] Mem abort info:
  [ 1147.971739][T17331]   ESR = 0x0000000096000004
  [ 1147.976172][T17331]   EC = 0x25: DABT (current EL), IL = 32 bits
  [ 1147.982171][T17331]   SET = 0, FnV = 0
  [ 1147.985906][T17331]   EA = 0, S1PTW = 0
  [ 1147.989734][T17331]   FSC = 0x04: level 0 translation fault
  [ 1147.995292][T17331] Data abort info:
  [ 1147.998858][T17331]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
  [ 1148.005023][T17331]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  [ 1148.010759][T17331]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
  [ 1148.016752][T17331] [dead000000000150] address between user and kernel address ranges
  [ 1148.024571][T17331] Internal error: Oops: 0000000096000004 [#1] SMP
  [ 1148.030825][T17331] Modules linked in: team_mode_loadbalance team nlmon act_gact cls_flower sch_ingress bonding tls macvlan dummy ib_core bridge stp llc veth amdgpu amdxcp mfd_core gpu_sched drm_exec drm_buddy radeon crct10dif_ce video drm_suballoc_helper ghash_ce drm_ttm_helper sha2_ce ttm sha256_arm64 i2c_algo_bit sha1_ce sbsa_gwdt cp210x drm_display_helper cec sr_mod cdrom drm_kms_helper binfmt_misc sg loop fuse drm dm_mod nfnetlink ip_tables autofs4 [last unloaded: tls]
  [ 1148.072808][T17331] CPU: 3 PID: 17331 Comm: ls Tainted: G        W         ------- ----  6.6.43 #2
  [ 1148.081751][T17331] Source Version: 21b3b386e948bedd29369af66f3e98ab01b1c650
  [ 1148.088783][T17331] Hardware name: Greatwall GW-001M1A-FTF/GW-001M1A-FTF, BIOS KunLun BIOS V4.0 07/16/2020
  [ 1148.098419][T17331] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  [ 1148.106060][T17331] pc : eventfs_iterate+0x2c0/0x398
  [ 1148.111017][T17331] lr : eventfs_iterate+0x2fc/0x398
  [ 1148.115969][T17331] sp : ffff80008d56bbd0
  [ 1148.119964][T17331] x29: ffff80008d56bbf0 x28: ffff001ff5be2600 x27: 0000000000000000
  [ 1148.127781][T17331] x26: ffff001ff52ca4e0 x25: 0000000000009977 x24: dead000000000100
  [ 1148.135598][T17331] x23: 0000000000000000 x22: 000000000000000b x21: ffff800082645f10
  [ 1148.143415][T17331] x20: ffff001fddf87c70 x19: ffff80008d56bc90 x18: 0000000000000000
  [ 1148.151231][T17331] x17: 0000000000000000 x16: 0000000000000000 x15: ffff001ff52ca4e0
  [ 1148.159048][T17331] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
  [ 1148.166864][T17331] x11: 0000000000000000 x10: 0000000000000000 x9 : ffff8000804391d0
  [ 1148.174680][T17331] x8 : 0000000180000000 x7 : 0000000000000018 x6 : 0000aaab04b92862
  [ 1148.182498][T17331] x5 : 0000aaab04b92862 x4 : 0000000080000000 x3 : 0000000000000068
  [ 1148.190314][T17331] x2 : 000000000000000f x1 : 0000000000007ea8 x0 : 0000000000000001
  [ 1148.198131][T17331] Call trace:
  [ 1148.201259][T17331]  eventfs_iterate+0x2c0/0x398
  [ 1148.205864][T17331]  iterate_dir+0x98/0x188
  [ 1148.210036][T17331]  __arm64_sys_getdents64+0x78/0x160
  [ 1148.215161][T17331]  invoke_syscall+0x78/0x108
  [ 1148.219593][T17331]  el0_svc_common.constprop.0+0x48/0xf0
  [ 1148.224977][T17331]  do_el0_svc+0x24/0x38
  [ 1148.228974][T17331]  el0_svc+0x40/0x168
  [ 1148.232798][T17331]  el0t_64_sync_handler+0x120/0x130
  [ 1148.237836][T17331]  el0t_64_sync+0x1a4/0x1a8
  [ 1148.242182][T17331] Code: 54ffff6c f9400676 910006d6 f9000676 (b9405300)
  [ 1148.248955][T17331] ---[ end trace 0000000000000000 ]---

The issue is that list_del() is used on an SRCU protected list variable
before the synchronization occurs. This can poison the list pointers while
there is a reader iterating the list.

This is simply fixed by using list_del_rcu() that is specifically made for
this purpose.

Link: https://lore.kernel.org/linux-trace-kernel/20240829085025.3600021-1-chizhiling@163.com/

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20240904131605.640d42b1@gandalf.local.home
Fixes: 43aa6f9 ("eventfs: Get rid of dentry pointers without refcounts")
Reported-by: Chi Zhiling <chizhiling@kylinos.cn>
Tested-by: Chi Zhiling <chizhiling@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit c68bbf5 ]

This adds a check before freeing the rx->skb in flush and close
functions to handle the kernel crash seen while removing driver after FW
download fails or before FW download completes.

dmesg log:
[   54.634586] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000080
[   54.643398] Mem abort info:
[   54.646204]   ESR = 0x0000000096000004
[   54.649964]   EC = 0x25: DABT (current EL), IL = 32 bits
[   54.655286]   SET = 0, FnV = 0
[   54.658348]   EA = 0, S1PTW = 0
[   54.661498]   FSC = 0x04: level 0 translation fault
[   54.666391] Data abort info:
[   54.669273]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[   54.674768]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[   54.674771]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[   54.674775] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000048860000
[   54.674780] [0000000000000080] pgd=0000000000000000, p4d=0000000000000000
[   54.703880] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
[   54.710152] Modules linked in: btnxpuart(-) overlay fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine authenc libdes crct10dif_ce polyval_ce polyval_generic snd_soc_imx_spdif snd_soc_imx_card snd_soc_ak5558 snd_soc_ak4458 caam secvio error snd_soc_fsl_micfil snd_soc_fsl_spdif snd_soc_fsl_sai snd_soc_fsl_utils imx_pcm_dma gpio_ir_recv rc_core sch_fq_codel fuse
[   54.744357] CPU: 3 PID: 72 Comm: kworker/u9:0 Not tainted 6.6.3-otbr-g128004619037 #2
[   54.744364] Hardware name: FSL i.MX8MM EVK board (DT)
[   54.744368] Workqueue: hci0 hci_power_on
[   54.757244] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   54.757249] pc : kfree_skb_reason+0x18/0xb0
[   54.772299] lr : btnxpuart_flush+0x40/0x58 [btnxpuart]
[   54.782921] sp : ffff8000805ebca0
[   54.782923] x29: ffff8000805ebca0 x28: ffffa5c6cf1869c0 x27: ffffa5c6cf186000
[   54.782931] x26: ffff377b84852400 x25: ffff377b848523c0 x24: ffff377b845e7230
[   54.782938] x23: ffffa5c6ce8dbe08 x22: ffffa5c6ceb65410 x21: 00000000ffffff92
[   54.782945] x20: ffffa5c6ce8dbe98 x19: ffffffffffffffac x18: ffffffffffffffff
[   54.807651] x17: 0000000000000000 x16: ffffa5c6ce2824ec x15: ffff8001005eb857
[   54.821917] x14: 0000000000000000 x13: ffffa5c6cf1a02e0 x12: 0000000000000642
[   54.821924] x11: 0000000000000040 x10: ffffa5c6cf19d690 x9 : ffffa5c6cf19d688
[   54.821931] x8 : ffff377b86000028 x7 : 0000000000000000 x6 : 0000000000000000
[   54.821938] x5 : ffff377b86000000 x4 : 0000000000000000 x3 : 0000000000000000
[   54.843331] x2 : 0000000000000000 x1 : 0000000000000002 x0 : ffffffffffffffac
[   54.857599] Call trace:
[   54.857601]  kfree_skb_reason+0x18/0xb0
[   54.863878]  btnxpuart_flush+0x40/0x58 [btnxpuart]
[   54.863888]  hci_dev_open_sync+0x3a8/0xa04
[   54.872773]  hci_power_on+0x54/0x2e4
[   54.881832]  process_one_work+0x138/0x260
[   54.881842]  worker_thread+0x32c/0x438
[   54.881847]  kthread+0x118/0x11c
[   54.881853]  ret_from_fork+0x10/0x20
[   54.896406] Code: a9be7bfd 910003fd f9000bf3 aa0003f3 (b940d400)
[   54.896410] ---[ end trace 0000000000000000 ]---

Signed-off-by: Neeraj Sanjay Kale <neeraj.sanjaykale@nxp.com>
Tested-by: Guillaume Legoupil <guillaume.legoupil@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 14, 2024
[ Upstream commit c3a5e3e ]

When using cachefiles, lockdep may emit something similar to the circular
locking dependency notice below.  The problem appears to stem from the
following:

 (1) Cachefiles manipulates xattrs on the files in its cache when called
     from ->writepages().

 (2) The setxattr() and removexattr() system call handlers get the name
     (and value) from userspace after taking the sb_writers lock, putting
     accesses of the vma->vm_lock and mm->mmap_lock inside of that.

 (3) The afs filesystem uses a per-inode lock to prevent multiple
     revalidation RPCs and in writeback vs truncate to prevent parallel
     operations from deadlocking against the server on one side and local
     page locks on the other.

Fix this by moving the getting of the name and value in {get,remove}xattr()
outside of the sb_writers lock.  This also has the minor benefits that we
don't need to reget these in the event of a retry and we never try to take
the sb_writers lock in the event we can't pull the name and value into the
kernel.

Alternative approaches that might fix this include moving the dispatch of a
write to the cache off to a workqueue or trying to do without the
validation lock in afs.  Note that this might also affect other filesystems
that use netfslib and/or cachefiles.

 ======================================================
 WARNING: possible circular locking dependency detected
 6.10.0-build2+ #956 Not tainted
 ------------------------------------------------------
 fsstress/6050 is trying to acquire lock:
 ffff888138fd82f0 (mapping.invalidate_lock#3){++++}-{3:3}, at: filemap_fault+0x26e/0x8b0

 but task is already holding lock:
 ffff888113f26d18 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x165/0x250

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #4 (&vma->vm_lock->lock){++++}-{3:3}:
        __lock_acquire+0xaf0/0xd80
        lock_acquire.part.0+0x103/0x280
        down_write+0x3b/0x50
        vma_start_write+0x6b/0xa0
        vma_link+0xcc/0x140
        insert_vm_struct+0xb7/0xf0
        alloc_bprm+0x2c1/0x390
        kernel_execve+0x65/0x1a0
        call_usermodehelper_exec_async+0x14d/0x190
        ret_from_fork+0x24/0x40
        ret_from_fork_asm+0x1a/0x30

 -> #3 (&mm->mmap_lock){++++}-{3:3}:
        __lock_acquire+0xaf0/0xd80
        lock_acquire.part.0+0x103/0x280
        __might_fault+0x7c/0xb0
        strncpy_from_user+0x25/0x160
        removexattr+0x7f/0x100
        __do_sys_fremovexattr+0x7e/0xb0
        do_syscall_64+0x9f/0x100
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #2 (sb_writers#14){.+.+}-{0:0}:
        __lock_acquire+0xaf0/0xd80
        lock_acquire.part.0+0x103/0x280
        percpu_down_read+0x3c/0x90
        vfs_iocb_iter_write+0xe9/0x1d0
        __cachefiles_write+0x367/0x430
        cachefiles_issue_write+0x299/0x2f0
        netfs_advance_write+0x117/0x140
        netfs_write_folio.isra.0+0x5ca/0x6e0
        netfs_writepages+0x230/0x2f0
        afs_writepages+0x4d/0x70
        do_writepages+0x1e8/0x3e0
        filemap_fdatawrite_wbc+0x84/0xa0
        __filemap_fdatawrite_range+0xa8/0xf0
        file_write_and_wait_range+0x59/0x90
        afs_release+0x10f/0x270
        __fput+0x25f/0x3d0
        __do_sys_close+0x43/0x70
        do_syscall_64+0x9f/0x100
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #1 (&vnode->validate_lock){++++}-{3:3}:
        __lock_acquire+0xaf0/0xd80
        lock_acquire.part.0+0x103/0x280
        down_read+0x95/0x200
        afs_writepages+0x37/0x70
        do_writepages+0x1e8/0x3e0
        filemap_fdatawrite_wbc+0x84/0xa0
        filemap_invalidate_inode+0x167/0x1e0
        netfs_unbuffered_write_iter+0x1bd/0x2d0
        vfs_write+0x22e/0x320
        ksys_write+0xbc/0x130
        do_syscall_64+0x9f/0x100
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 -> #0 (mapping.invalidate_lock#3){++++}-{3:3}:
        check_noncircular+0x119/0x160
        check_prev_add+0x195/0x430
        __lock_acquire+0xaf0/0xd80
        lock_acquire.part.0+0x103/0x280
        down_read+0x95/0x200
        filemap_fault+0x26e/0x8b0
        __do_fault+0x57/0xd0
        do_pte_missing+0x23b/0x320
        __handle_mm_fault+0x2d4/0x320
        handle_mm_fault+0x14f/0x260
        do_user_addr_fault+0x2a2/0x500
        exc_page_fault+0x71/0x90
        asm_exc_page_fault+0x22/0x30

 other info that might help us debug this:

 Chain exists of:
   mapping.invalidate_lock#3 --> &mm->mmap_lock --> &vma->vm_lock->lock

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   rlock(&vma->vm_lock->lock);
                                lock(&mm->mmap_lock);
                                lock(&vma->vm_lock->lock);
   rlock(mapping.invalidate_lock#3);

  *** DEADLOCK ***

 1 lock held by fsstress/6050:
  #0: ffff888113f26d18 (&vma->vm_lock->lock){++++}-{3:3}, at: lock_vma_under_rcu+0x165/0x250

 stack backtrace:
 CPU: 0 PID: 6050 Comm: fsstress Not tainted 6.10.0-build2+ #956
 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x57/0x80
  check_noncircular+0x119/0x160
  ? queued_spin_lock_slowpath+0x4be/0x510
  ? __pfx_check_noncircular+0x10/0x10
  ? __pfx_queued_spin_lock_slowpath+0x10/0x10
  ? mark_lock+0x47/0x160
  ? init_chain_block+0x9c/0xc0
  ? add_chain_block+0x84/0xf0
  check_prev_add+0x195/0x430
  __lock_acquire+0xaf0/0xd80
  ? __pfx___lock_acquire+0x10/0x10
  ? __lock_release.isra.0+0x13b/0x230
  lock_acquire.part.0+0x103/0x280
  ? filemap_fault+0x26e/0x8b0
  ? __pfx_lock_acquire.part.0+0x10/0x10
  ? rcu_is_watching+0x34/0x60
  ? lock_acquire+0xd7/0x120
  down_read+0x95/0x200
  ? filemap_fault+0x26e/0x8b0
  ? __pfx_down_read+0x10/0x10
  ? __filemap_get_folio+0x25/0x1a0
  filemap_fault+0x26e/0x8b0
  ? __pfx_filemap_fault+0x10/0x10
  ? find_held_lock+0x7c/0x90
  ? __pfx___lock_release.isra.0+0x10/0x10
  ? __pte_offset_map+0x99/0x110
  __do_fault+0x57/0xd0
  do_pte_missing+0x23b/0x320
  __handle_mm_fault+0x2d4/0x320
  ? __pfx___handle_mm_fault+0x10/0x10
  handle_mm_fault+0x14f/0x260
  do_user_addr_fault+0x2a2/0x500
  exc_page_fault+0x71/0x90
  asm_exc_page_fault+0x22/0x30

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/2136178.1721725194@warthog.procyon.org.uk
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Christian Brauner <brauner@kernel.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: Gao Xiang <xiang@kernel.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-erofs@lists.ozlabs.org
cc: linux-fsdevel@vger.kernel.org
[brauner: fix minor issues]
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
…-level'

Eduard Zingerman says:

====================
bpf: track find_equal_scalars history on per-instruction level

This is a fix for precision tracking bug reported in [0].
It supersedes my previous attempt to fix similar issue in commit [1].
Here is a minimized test case from [0]:

    0:  call bpf_get_prandom_u32;
    1:  r7 = r0;
    2:  r8 = r0;
    3:  call bpf_get_prandom_u32;
    4:  if r0 > 1 goto +0;
    /* --- checkpoint #1: r7.id=1, r8.id=1 --- */
    5:  if r8 >= r0 goto 9f;
    6:  r8 += r8;
    /* --- checkpoint #2: r7.id=1, r8.id=0 --- */
    7:  if r7 == 0 goto 9f;
    8:  r0 /= 0;
    /* --- checkpoint #3 --- */
    9:  r0 = 42;
    10: exit;

W/o this fix verifier incorrectly assumes that instruction at label
(8) is unreachable. The issue is caused by failure to infer
precision mark for r0 at checkpoint #1:
- first verification path is:
  - (0-4): r0 range [0,1];
  - (5): r8 range [0,0], propagated to r7;
  - (6): r8.id is reset;
  - (7): jump is predicted to happen;
  - (9-10): safe exit.
- when jump at (7) is predicted mark_chain_precision() for r7 is
  called and backtrack_insn() proceeds as follows:
  - at (7) r7 is marked as precise;
  - at (5) r8 is not currently tracked and thus r0 is not marked;
  - at (4-5) boundary logic from [1] is triggered and r7,r8 are marked
    as precise;
  - => r0 precision mark is missed.
- when second branch of (4) is considered, verifier prunes the state
  because r0 is not marked as precise in the visited state.

Basically, backtracking logic fails to notice that at (5)
range information is gained for both r7 and r8, and thus both
r8 and r0 have to be marked as precise.
This happens because [1] can only account for such range
transfers at parent/child state boundaries.

The solution suggested by Andrii Nakryiko in [0] is to use jump
history to remember which registers gained range as a result of
find_equal_scalars() [renamed to sync_linked_regs()] and use
this information in backtrack_insn().
Which is what this patch-set does.

The patch-set uses u64 value as a vector of 10-bit values that
identify registers gaining range in find_equal_scalars().
This amounts to maximum of 6 possible values.
To check if such capacity is sufficient I've instrumented kernel
to track a histogram for maximal amount of registers that gain range
in find_equal_scalars per program verification [2].
Measurements done for verifier selftests and Cilium bpf object files
from [3] show that number of such registers is *always* <= 4 and
in 98% of cases it is <= 2.

When tested on a subset of selftests identified by
selftests/bpf/veristat.cfg and Cilium bpf object files from [3]
this patch-set has minimal verification performance impact:

File                      Program                   Insns   (DIFF)  States (DIFF)
------------------------  ------------------------  --------------  -------------
bpf_host.o                tail_handle_nat_fwd_ipv4    -75 (-0.61%)    -3 (-0.39%)
pyperf600_nounroll.bpf.o  on_event                  +1673 (+0.33%)    +3 (+0.01%)

[0] https://lore.kernel.org/bpf/CAEf4BzZ0xidVCqB47XnkXcNhkPWF6_nTV7yt+_Lf0kcFEut2Mg@mail.gmail.com/
[1] commit 904e6dd ("bpf: Use scalar ids in mark_chain_precision()")
[2] https://github.com/eddyz87/bpf/tree/find-equal-scalars-in-jump-history-with-stats
[3] https://github.com/anakryiko/cilium

Changes:
- v2 -> v3:
  A number of stylistic changes suggested by Andrii:
  - renamings:
    - struct reg_or_spill   -> linked_reg;
    - find_equal_scalars()  -> collect_linked_regs;
    - copy_known_reg()      -> sync_linked_regs;
  - collect_linked_regs() now returns linked regs set of
    size 2 or larger;
  - dropped usage of bit fields in struct linked_reg;
  - added a patch changing references to find_equal_scalars() in
    selftests comments.
- v1 -> v2:
  - patch "bpf: replace env->cur_hist_ent with a getter function" is
    dropped (Andrii);
  - added structure linked_regs and helper functions to [de]serialize
    u64 value as such structure (Andrii);
  - bt_set_equal_scalars() renamed to bt_sync_linked_regs(), moved to
    start and end of backtrack_insn() in order to untie linked
    register logic from conditional jumps backtracking.
    Andrii requested a more radical change of moving linked registers
    processing to bt_set_xxx() functions, I did an experiment in this
    direction:
    https://github.com/eddyz87/bpf/tree/find-equal-scalars-in-jump-history--linked-regs-in-bt-set-reg
    the end result of the experiment seems much uglier than version
    presented in v2.

Revisions:
- v1: https://lore.kernel.org/bpf/20240222005005.31784-1-eddyz87@gmail.com/
- v2: https://lore.kernel.org/bpf/20240705205851.2635794-1-eddyz87@gmail.com/
====================

Link: https://lore.kernel.org/r/20240718202357.1746514-1-eddyz87@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
Leak sanitizer will report memory leaks from python and the leak
sanitizer output causes tests to fail. For example:

  ```
  $ perf test 98 -v
   98: perf script tests:
  --- start ---
  test child forked, pid 1272962
  DB test
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.046 MB /tmp/perf-test-script.x0EktdCel8/perf.data (8 samples) ]
  call_path_table((1, 0, 0, 0)
  call_path_table((2, 1, 0, 140339508617447)
  call_path_table((3, 2, 2, 0)
  call_path_table((4, 3, 3, 0)
  call_path_table((5, 4, 4, 0)
  call_path_table((6, 5, 5, 0)
  call_path_table((7, 6, 6, 0)
  call_path_table((8, 7, 7, 0)
  call_path_table((9, 8, 8, 0)
  call_path_table((10, 9, 9, 0)
  call_path_table((11, 10, 10, 0)
  call_path_table((12, 11, 11, 0)
  call_path_table((13, 12, 1, 0)
  sample_table((1, 1, 1, 1, 1, 1, 1, 8, -2058824120, 588306954119000, -1, 0, 0, 0, 0, 1, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  sample_table((2, 1, 1, 1, 1, 1, 1, 8, -2058824120, 588306954137053, -1, 0, 0, 0, 0, 1, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  sample_table((3, 1, 1, 1, 1, 1, 1, 8, -2058824120, 588306954140089, -1, 0, 0, 0, 0, 9, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  sample_table((4, 1, 1, 1, 1, 1, 1, 8, -2058824120, 588306954142376, -1, 0, 0, 0, 0, 155, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  sample_table((5, 1, 1, 1, 1, 1, 1, 8, -2058824120, 588306954144045, -1, 0, 0, 0, 0, 2493, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  sample_table((6, 1, 1, 1, 1, 1, 12, 77, -2046828595, 588306954145722, -1, 0, 0, 0, 0, 47555, 0, 0, 128933429281, 0, 0, 13, 0, 0, 0, -1, -1))
  call_path_table((14, 9, 14, 0)
  call_path_table((15, 14, 15, 0)
  call_path_table((16, 15, 0, -1040969624)
  call_path_table((17, 16, 16, 0)
  call_path_table((18, 17, 17, 0)
  call_path_table((19, 18, 18, 0)
  call_path_table((20, 19, 19, 0)
  call_path_table((21, 20, 13, 0)
  sample_table((7, 1, 1, 1, 2, 1, 13, 46, -2053700898, 588306954157436, -1, 0, 0, 0, 0, 964078, 0, 0, 128933429281, 0, 0, 21, 0, 0, 0, -1, -1))
  call_path_table((22, 1, 21, 0)
  call_path_table((23, 22, 22, 0)
  call_path_table((24, 23, 23, 0)
  call_path_table((25, 24, 24, 0)
  call_path_table((26, 25, 25, 0)
  call_path_table((27, 26, 26, 0)
  call_path_table((28, 27, 27, 0)
  call_path_table((29, 28, 28, 0)
  call_path_table((30, 29, 29, 0)
  call_path_table((31, 30, 30, 0)
  call_path_table((32, 31, 31, 0)
  call_path_table((33, 32, 32, 0)
  call_path_table((34, 33, 33, 0)
  call_path_table((35, 34, 20, 0)
  sample_table((8, 1, 1, 1, 2, 1, 20, 49, -2046878127, 588306954378624, -1, 0, 0, 0, 0, 2534317, 0, 0, 128933429281, 0, 0, 35, 0, 0, 0, -1, -1))

  =================================================================
  ==1272975==ERROR: LeakSanitizer: detected memory leaks

  Direct leak of 13628 byte(s) in 6 object(s) allocated from:
      #0 0x56354f60c092 in malloc (/tmp/perf/perf+0x29c092)
      #1 0x7ff25c7d02e7 in _PyObject_Malloc /build/python3.11/../Objects/obmalloc.c:2003:11
      #2 0x7ff25c7d02e7 in _PyObject_Malloc /build/python3.11/../Objects/obmalloc.c:1996:1

  SUMMARY: AddressSanitizer: 13628 byte(s) leaked in 6 allocation(s).
  --- Cleaning up ---
  ---- end(-1) ----
   98: perf script tests                                               : FAILED!
  ```

Disable leak sanitizer when running specific perf+python tests to
avoid this. This causes the tests to pass when run with leak
sanitizer.

Reviewed-by: Aditya Gupta <adityag@linux.ibm.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
iter_finish_branch_entry() doesn't put the branch_info from/to map
elements creating memory leaks. This can be seen with:

```
$ perf record -e cycles -b perf test -w noploop
$ perf report -D
...
Direct leak of 984344 byte(s) in 123043 object(s) allocated from:
    #0 0x7fb2654f3bd7 in malloc libsanitizer/asan/asan_malloc_linux.cpp:69
    #1 0x564d3400d10b in map__get util/map.h:186
    #2 0x564d3400d10b in ip__resolve_ams util/machine.c:1981
    #3 0x564d34014d81 in sample__resolve_bstack util/machine.c:2151
    #4 0x564d34094790 in iter_prepare_branch_entry util/hist.c:898
    #5 0x564d34098fa4 in hist_entry_iter__add util/hist.c:1238
    #6 0x564d33d1f0c7 in process_sample_event tools/perf/builtin-report.c:334
    #7 0x564d34031eb7 in perf_session__deliver_event util/session.c:1655
    #8 0x564d3403ba52 in do_flush util/ordered-events.c:245
    #9 0x564d3403ba52 in __ordered_events__flush util/ordered-events.c:324
    #10 0x564d3402d32e in perf_session__process_user_event util/session.c:1708
    #11 0x564d34032480 in perf_session__process_event util/session.c:1877
    #12 0x564d340336ad in reader__read_event util/session.c:2399
    #13 0x564d34033fdc in reader__process_events util/session.c:2448
    #14 0x564d34033fdc in __perf_session__process_events util/session.c:2495
    #15 0x564d34033fdc in perf_session__process_events util/session.c:2661
    #16 0x564d33d27113 in __cmd_report tools/perf/builtin-report.c:1065
    #17 0x564d33d27113 in cmd_report tools/perf/builtin-report.c:1805
    #18 0x564d33e0ccb7 in run_builtin tools/perf/perf.c:350
    #19 0x564d33e0d45e in handle_internal_command tools/perf/perf.c:403
    #20 0x564d33cdd827 in run_argv tools/perf/perf.c:447
    #21 0x564d33cdd827 in main tools/perf/perf.c:561
...
```

Clearing up the map_symbols properly creates maps reference count
issues so resolve those. Resolving this issue doesn't improve peak
heap consumption for the test above.

Committer testing:

  $ sudo dnf install libasan
  $ make -k CORESIGHT=1 EXTRA_CFLAGS="-fsanitize=address" CC=clang O=/tmp/build/$(basename $PWD)/ -C tools/perf install-bin

Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sun Haiyong <sunhaiyong@loongson.cn>
Cc: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/20240807065136.1039977-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
AddressSanitizer found a use-after-free bug in the symbol code which
manifested as 'perf top' segfaulting.

  ==1238389==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b00c48844b at pc 0x5650d8035961 bp 0x7f751aaecc90 sp 0x7f751aaecc80
  READ of size 1 at 0x60b00c48844b thread T193
      #0 0x5650d8035960 in _sort__sym_cmp util/sort.c:310
      #1 0x5650d8043744 in hist_entry__cmp util/hist.c:1286
      #2 0x5650d8043951 in hists__findnew_entry util/hist.c:614
      #3 0x5650d804568f in __hists__add_entry util/hist.c:754
      #4 0x5650d8045bf9 in hists__add_entry util/hist.c:772
      #5 0x5650d8045df1 in iter_add_single_normal_entry util/hist.c:997
      #6 0x5650d8043326 in hist_entry_iter__add util/hist.c:1242
      #7 0x5650d7ceeefe in perf_event__process_sample /home/matt/src/linux/tools/perf/builtin-top.c:845
      #8 0x5650d7ceeefe in deliver_event /home/matt/src/linux/tools/perf/builtin-top.c:1208
      #9 0x5650d7fdb51b in do_flush util/ordered-events.c:245
      #10 0x5650d7fdb51b in __ordered_events__flush util/ordered-events.c:324
      #11 0x5650d7ced743 in process_thread /home/matt/src/linux/tools/perf/builtin-top.c:1120
      #12 0x7f757ef1f133 in start_thread nptl/pthread_create.c:442
      #13 0x7f757ef9f7db in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81

When updating hist maps it's also necessary to update the hist symbol
reference because the old one gets freed in map__put().

While this bug was probably introduced with 5c24b67 ("perf
tools: Replace map->referenced & maps->removed_maps with map->refcnt"),
the symbol objects were leaked until c087e94 ("perf machine:
Fix refcount usage when processing PERF_RECORD_KSYMBOL") was merged so
the bug was masked.

Fixes: c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL")
Reported-by: Yunzhao Li <yunzhao@cloudflare.com>
Signed-off-by: Matt Fleming (Cloudflare) <matt@readmodwrite.com>
Cc: Ian Rogers <irogers@google.com>
Cc: kernel-team@cloudflare.com
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: stable@vger.kernel.org # v5.13+
Link: https://lore.kernel.org/r/20240815142212.3834625-1-matt@readmodwrite.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
Eduard Zingerman says:

====================
__jited test tag to check disassembly after jit

Some of the logic in the BPF jits might be non-trivial.
It might be useful to allow testing this logic by comparing
generated native code with expected code template.
This patch set adds a macro __jited() that could be used for
test_loader based tests in a following manner:

    SEC("tp")
    __arch_x86_64
    __jited("   endbr64")
    __jited("   nopl    (%rax,%rax)")
    __jited("   xorq    %rax, %rax")
    ...
    __naked void some_test(void) { ... }

Also add a test for jit code generated for tail calls handling to
demonstrate the feature.

The feature uses LLVM libraries to do the disassembly.
At selftests compilation time Makefile detects if these libraries are
available. When libraries are not available tests using __jit_x86()
are skipped.
Current CI environment does not include llvm development libraries,
but changes to add these are trivial.

This was previously discussed here:
https://lore.kernel.org/bpf/20240718205158.3651529-1-yonghong.song@linux.dev/

Patch-set includes a few auxiliary steps:
- patches #2 and #3 fix a few bugs in test_loader behaviour;
- patch #4 replaces __regex macro with ability to specify regular
  expressions in __msg and __xlated using "{{" "}}" escapes;
- patch #8 updates __xlated to match disassembly lines consequently,
  same way as __jited does.

Changes v2->v3:
- changed macro name from __jit_x86 to __jited with __arch_* to
  specify disassembly arch (Yonghong);
- __jited matches disassembly lines consequently with "..."
  allowing to skip some number of lines (Andrii);
- __xlated matches disassembly lines consequently, same as __jited;
- "{{...}}" regex brackets instead of __regex macro;
- bug fixes for old commits.

Changes v1->v2:
- stylistic changes suggested by Yonghong;
- fix for -Wformat-truncation related warning when compiled with
  llvm15 (Yonghong).

v1: https://lore.kernel.org/bpf/20240809010518.1137758-1-eddyz87@gmail.com/
v2: https://lore.kernel.org/bpf/20240815205449.242556-1-eddyz87@gmail.com/
====================

Link: https://lore.kernel.org/r/20240820102357.3372779-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
Add nested locking with I_MUTEX_XATTR subclass to avoid lockdep warning
while handling xattr inode on file open syscall at ext4_xattr_inode_iget.

Backtrace
EXT4-fs (loop0): Ignoring removed oldalloc option
======================================================
WARNING: possible circular locking dependency detected
5.10.0-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor543/2794 is trying to acquire lock:
ffff8880215e1a48 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:782 [inline]
ffff8880215e1a48 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}, at: ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425

but task is already holding lock:
ffff8880215e3278 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x136d/0x19c0 fs/ext4/inode.c:5559

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ei->i_data_sem/3){++++}-{3:3}:
       lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566
       down_write+0x93/0x180 kernel/locking/rwsem.c:1564
       ext4_update_i_disksize fs/ext4/ext4.h:3267 [inline]
       ext4_xattr_inode_write fs/ext4/xattr.c:1390 [inline]
       ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1538 [inline]
       ext4_xattr_set_entry+0x331a/0x3d80 fs/ext4/xattr.c:1662
       ext4_xattr_ibody_set+0x124/0x390 fs/ext4/xattr.c:2228
       ext4_xattr_set_handle+0xc27/0x14e0 fs/ext4/xattr.c:2385
       ext4_xattr_set+0x219/0x390 fs/ext4/xattr.c:2498
       ext4_xattr_user_set+0xc9/0xf0 fs/ext4/xattr_user.c:40
       __vfs_setxattr+0x404/0x450 fs/xattr.c:177
       __vfs_setxattr_noperm+0x11d/0x4f0 fs/xattr.c:208
       __vfs_setxattr_locked+0x1f9/0x210 fs/xattr.c:266
       vfs_setxattr+0x112/0x2c0 fs/xattr.c:283
       setxattr+0x1db/0x3e0 fs/xattr.c:548
       path_setxattr+0x15a/0x240 fs/xattr.c:567
       __do_sys_setxattr fs/xattr.c:582 [inline]
       __se_sys_setxattr fs/xattr.c:578 [inline]
       __x64_sys_setxattr+0xc5/0xe0 fs/xattr.c:578
       do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

-> #0 (&ea_inode->i_rwsem#7/1){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:2988 [inline]
       check_prevs_add kernel/locking/lockdep.c:3113 [inline]
       validate_chain+0x1695/0x58f0 kernel/locking/lockdep.c:3729
       __lock_acquire+0x12fd/0x20d0 kernel/locking/lockdep.c:4955
       lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566
       down_write+0x93/0x180 kernel/locking/rwsem.c:1564
       inode_lock include/linux/fs.h:782 [inline]
       ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425
       ext4_xattr_inode_get+0x138/0x410 fs/ext4/xattr.c:485
       ext4_xattr_move_to_block fs/ext4/xattr.c:2580 [inline]
       ext4_xattr_make_inode_space fs/ext4/xattr.c:2682 [inline]
       ext4_expand_extra_isize_ea+0xe70/0x1bb0 fs/ext4/xattr.c:2774
       __ext4_expand_extra_isize+0x304/0x3f0 fs/ext4/inode.c:5898
       ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline]
       __ext4_mark_inode_dirty+0x591/0x810 fs/ext4/inode.c:6018
       ext4_setattr+0x1400/0x19c0 fs/ext4/inode.c:5562
       notify_change+0xbb6/0xe60 fs/attr.c:435
       do_truncate+0x1de/0x2c0 fs/open.c:64
       handle_truncate fs/namei.c:2970 [inline]
       do_open fs/namei.c:3311 [inline]
       path_openat+0x29f3/0x3290 fs/namei.c:3425
       do_filp_open+0x20b/0x450 fs/namei.c:3452
       do_sys_openat2+0x124/0x460 fs/open.c:1207
       do_sys_open fs/open.c:1223 [inline]
       __do_sys_open fs/open.c:1231 [inline]
       __se_sys_open fs/open.c:1227 [inline]
       __x64_sys_open+0x221/0x270 fs/open.c:1227
       do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62
       entry_SYSCALL_64_after_hwframe+0x61/0xcb

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->i_data_sem/3);
                               lock(&ea_inode->i_rwsem#7/1);
                               lock(&ei->i_data_sem/3);
  lock(&ea_inode->i_rwsem#7/1);

 *** DEADLOCK ***

5 locks held by syz-executor543/2794:
 #0: ffff888026fbc448 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x4a/0x2a0 fs/namespace.c:365
 #1: ffff8880215e3488 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:782 [inline]
 #1: ffff8880215e3488 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: do_truncate+0x1cf/0x2c0 fs/open.c:62
 #2: ffff8880215e3310 (&ei->i_mmap_sem){++++}-{3:3}, at: ext4_setattr+0xec4/0x19c0 fs/ext4/inode.c:5519
 #3: ffff8880215e3278 (&ei->i_data_sem/3){++++}-{3:3}, at: ext4_setattr+0x136d/0x19c0 fs/ext4/inode.c:5559
 #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_trylock_xattr fs/ext4/xattr.h:162 [inline]
 #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_try_to_expand_extra_isize fs/ext4/inode.c:5938 [inline]
 #4: ffff8880215e30c8 (&ei->xattr_sem){++++}-{3:3}, at: __ext4_mark_inode_dirty+0x4fb/0x810 fs/ext4/inode.c:6018

stack backtrace:
CPU: 1 PID: 2794 Comm: syz-executor543 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x177/0x211 lib/dump_stack.c:118
 print_circular_bug+0x146/0x1b0 kernel/locking/lockdep.c:2002
 check_noncircular+0x2cc/0x390 kernel/locking/lockdep.c:2123
 check_prev_add kernel/locking/lockdep.c:2988 [inline]
 check_prevs_add kernel/locking/lockdep.c:3113 [inline]
 validate_chain+0x1695/0x58f0 kernel/locking/lockdep.c:3729
 __lock_acquire+0x12fd/0x20d0 kernel/locking/lockdep.c:4955
 lock_acquire+0x197/0x480 kernel/locking/lockdep.c:5566
 down_write+0x93/0x180 kernel/locking/rwsem.c:1564
 inode_lock include/linux/fs.h:782 [inline]
 ext4_xattr_inode_iget+0x42a/0x5c0 fs/ext4/xattr.c:425
 ext4_xattr_inode_get+0x138/0x410 fs/ext4/xattr.c:485
 ext4_xattr_move_to_block fs/ext4/xattr.c:2580 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2682 [inline]
 ext4_expand_extra_isize_ea+0xe70/0x1bb0 fs/ext4/xattr.c:2774
 __ext4_expand_extra_isize+0x304/0x3f0 fs/ext4/inode.c:5898
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5941 [inline]
 __ext4_mark_inode_dirty+0x591/0x810 fs/ext4/inode.c:6018
 ext4_setattr+0x1400/0x19c0 fs/ext4/inode.c:5562
 notify_change+0xbb6/0xe60 fs/attr.c:435
 do_truncate+0x1de/0x2c0 fs/open.c:64
 handle_truncate fs/namei.c:2970 [inline]
 do_open fs/namei.c:3311 [inline]
 path_openat+0x29f3/0x3290 fs/namei.c:3425
 do_filp_open+0x20b/0x450 fs/namei.c:3452
 do_sys_openat2+0x124/0x460 fs/open.c:1207
 do_sys_open fs/open.c:1223 [inline]
 __do_sys_open fs/open.c:1231 [inline]
 __se_sys_open fs/open.c:1227 [inline]
 __x64_sys_open+0x221/0x270 fs/open.c:1227
 do_syscall_64+0x6d/0xa0 arch/x86/entry/common.c:62
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f0cde4ea229
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd81d1c978 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0030656c69662f30 RCX: 00007f0cde4ea229
RDX: 0000000000000089 RSI: 00000000000a0a00 RDI: 00000000200001c0
RBP: 2f30656c69662f2e R08: 0000000000208000 R09: 0000000000208000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd81d1c9c0
R13: 00007ffd81d1ca00 R14: 0000000000080000 R15: 0000000000000003
EXT4-fs error (device loop0): ext4_expand_extra_isize_ea:2730: inode #13: comm syz-executor543: corrupted in-inode xattr

Signed-off-by: Wojciech Gładysz <wojciech.gladysz@infogain.com>
Link: https://patch.msgid.link/20240801143827.19135-1-wojciech.gladysz@infogain.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
The fields in the hist_entry are filled on-demand which means they only
have meaningful values when relevant sort keys are used.

So if neither of 'dso' nor 'sym' sort keys are used, the map/symbols in
the hist entry can be garbage.  So it shouldn't access it
unconditionally.

I got a segfault, when I wanted to see cgroup profiles.

  $ sudo perf record -a --all-cgroups --synth=cgroup true

  $ sudo perf report -s cgroup

  Program received signal SIGSEGV, Segmentation fault.
  0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
  48		return RC_CHK_ACCESS(map)->dso;
  (gdb) bt
  #0  0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48
  #1  0x00005555557aa39b in map__load (map=0x0) at util/map.c:344
  #2  0x00005555557aa592 in map__find_symbol (map=0x0, addr=140736115941088) at util/map.c:385
  #3  0x00005555557ef000 in hists__findnew_entry (hists=0x555556039d60, entry=0x7fffffffa4c0, al=0x7fffffffa8c0, sample_self=true)
      at util/hist.c:644
  #4  0x00005555557ef61c in __hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
      block_info=0x0, sample=0x7fffffffaa90, sample_self=true, ops=0x0) at util/hist.c:761
  #5  0x00005555557ef71f in hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0,
      sample=0x7fffffffaa90, sample_self=true) at util/hist.c:779
  #6  0x00005555557f00fb in iter_add_single_normal_entry (iter=0x7fffffffa900, al=0x7fffffffa8c0) at util/hist.c:1015
  #7  0x00005555557f09a7 in hist_entry_iter__add (iter=0x7fffffffa900, al=0x7fffffffa8c0, max_stack_depth=127, arg=0x7fffffffbce0)
      at util/hist.c:1260
  #8  0x00005555555ba7ce in process_sample_event (tool=0x7fffffffbce0, event=0x7ffff7c14128, sample=0x7fffffffaa90, evsel=0x555556039ad0,
      machine=0x5555560388e8) at builtin-report.c:334
  #9  0x00005555557b30c8 in evlist__deliver_sample (evlist=0x555556039010, tool=0x7fffffffbce0, event=0x7ffff7c14128,
      sample=0x7fffffffaa90, evsel=0x555556039ad0, machine=0x5555560388e8) at util/session.c:1232
  #10 0x00005555557b32bc in machines__deliver_event (machines=0x5555560388e8, evlist=0x555556039010, event=0x7ffff7c14128,
      sample=0x7fffffffaa90, tool=0x7fffffffbce0, file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1271
  #11 0x00005555557b3848 in perf_session__deliver_event (session=0x5555560386d0, event=0x7ffff7c14128, tool=0x7fffffffbce0,
      file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1354
  #12 0x00005555557affaf in ordered_events__deliver_event (oe=0x555556038e60, event=0x555556135aa0) at util/session.c:132
  #13 0x00005555557bb605 in do_flush (oe=0x555556038e60, show_progress=false) at util/ordered-events.c:245
  #14 0x00005555557bb95c in __ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND, timestamp=0) at util/ordered-events.c:324
  #15 0x00005555557bba46 in ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND) at util/ordered-events.c:342
  #16 0x00005555557b1b3b in perf_event__process_finished_round (tool=0x7fffffffbce0, event=0x7ffff7c15bb8, oe=0x555556038e60)
      at util/session.c:780
  #17 0x00005555557b3b27 in perf_session__process_user_event (session=0x5555560386d0, event=0x7ffff7c15bb8, file_offset=117688,
      file_path=0x555556038ff0 "perf.data") at util/session.c:1406

As you can see the entry->ms.map was NULL even if he->ms.map has a
value.  This is because 'sym' sort key is not given, so it cannot assume
whether he->ms.sym and entry->ms.sym is the same.  I only checked the
'sym' sort key here as it implies 'dso' behavior (so maps are the same).

Fixes: ac01c8c ("perf hist: Update hist symbol when updating maps")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Matt Fleming <matt@readmodwrite.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240826221045.1202305-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
…ptions

Patch series "mm: split PTE/PMD PT table Kconfig cleanups+clarifications".

This series is a follow up to the fixes:
	"[PATCH v1 0/2] mm/hugetlb: fix hugetlb vs. core-mm PT locking"

When working on the fixes, I wondered why 8xx is fine (-> never uses split
PT locks) and how PT locking even works properly with PMD page table
sharing (-> always requires split PMD PT locks).

Let's improve the split PT lock detection, make hugetlb properly depend on
it and make 8xx bail out if it would ever get enabled by accident.

As an alternative to patch #3 we could extend the Kconfig
SPLIT_PTE_PTLOCKS option from patch #2 -- but enforcing it closer to the
code that actually implements it feels a bit nicer for documentation
purposes, and there is no need to actually disable it because it should
always be disabled (!SMP).

Did a bunch of cross-compilations to make sure that split PTE/PMD PT locks
are still getting used where we would expect them.

[1] https://lkml.kernel.org/r/20240725183955.2268884-1-david@redhat.com


This patch (of 3):

Let's clean that up a bit and prepare for depending on
CONFIG_SPLIT_PMD_PTLOCKS in other Kconfig options.

More cleanups would be reasonable (like the arch-specific "depends on" for
CONFIG_SPLIT_PTE_PTLOCKS), but we'll leave that for another day.

Link: https://lkml.kernel.org/r/20240726150728.3159964-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240726150728.3159964-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
commit 823430c ("memory tier: consolidate the initialization of
memory tiers") introduces a locking change that use guard(mutex) to
instead of mutex_lock/unlock() for memory_tier_lock.  It unexpectedly
expanded the locked region to include the hotplug_memory_notifier(), as a
result, it triggers an locking dependency detected of ABBA deadlock. 
Exclude hotplug_memory_notifier() from the locked region to fixing it.

The deadlock scenario is that when a memory online event occurs, the
execution of memory notifier will access the read lock of the
memory_chain.rwsem, then the reigistration of the memory notifier in
memory_tier_init() acquires the write lock of the memory_chain.rwsem while
holding memory_tier_lock.  Then the memory online event continues to
invoke the memory hotplug callback registered by memory_tier_init(). 
Since this callback tries to acquire the memory_tier_lock, a deadlock
occurs.

In fact, this deadlock can't happen because memory_tier_init() always
executes before memory online events happen due to the subsys_initcall()
has an higher priority than module_init().

[  133.491106] WARNING: possible circular locking dependency detected
[  133.493656] 6.11.0-rc2+ #146 Tainted: G           O     N
[  133.504290] ------------------------------------------------------
[  133.515194] (udev-worker)/1133 is trying to acquire lock:
[  133.525715] ffffffff87044e28 (memory_tier_lock){+.+.}-{3:3}, at: memtier_hotplug_callback+0x383/0x4b0
[  133.536449]
[  133.536449] but task is already holding lock:
[  133.549847] ffffffff875d3310 ((memory_chain).rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x60/0xb0
[  133.556781]
[  133.556781] which lock already depends on the new lock.
[  133.556781]
[  133.569957]
[  133.569957] the existing dependency chain (in reverse order) is:
[  133.577618]
[  133.577618] -> #1 ((memory_chain).rwsem){++++}-{3:3}:
[  133.584997]        down_write+0x97/0x210
[  133.588647]        blocking_notifier_chain_register+0x71/0xd0
[  133.592537]        register_memory_notifier+0x26/0x30
[  133.596314]        memory_tier_init+0x187/0x300
[  133.599864]        do_one_initcall+0x117/0x5d0
[  133.603399]        kernel_init_freeable+0xab0/0xeb0
[  133.606986]        kernel_init+0x28/0x2f0
[  133.610312]        ret_from_fork+0x59/0x90
[  133.613652]        ret_from_fork_asm+0x1a/0x30
[  133.617012]
[  133.617012] -> #0 (memory_tier_lock){+.+.}-{3:3}:
[  133.623390]        __lock_acquire+0x2efd/0x5c60
[  133.626730]        lock_acquire+0x1ce/0x580
[  133.629757]        __mutex_lock+0x15c/0x1490
[  133.632731]        mutex_lock_nested+0x1f/0x30
[  133.635717]        memtier_hotplug_callback+0x383/0x4b0
[  133.638748]        notifier_call_chain+0xbf/0x370
[  133.641647]        blocking_notifier_call_chain+0x76/0xb0
[  133.644636]        memory_notify+0x2e/0x40
[  133.647427]        online_pages+0x597/0x720
[  133.650246]        memory_subsys_online+0x4f6/0x7f0
[  133.653107]        device_online+0x141/0x1d0
[  133.655831]        online_memory_block+0x4d/0x60
[  133.658616]        walk_memory_blocks+0xc0/0x120
[  133.661419]        add_memory_resource+0x51d/0x6c0
[  133.664202]        add_memory_driver_managed+0xf5/0x180
[  133.667060]        dev_dax_kmem_probe+0x7f7/0xb40 [kmem]
[  133.669949]        dax_bus_probe+0x147/0x230
[  133.672687]        really_probe+0x27f/0xac0
[  133.675463]        __driver_probe_device+0x1f3/0x460
[  133.678493]        driver_probe_device+0x56/0x1b0
[  133.681366]        __driver_attach+0x277/0x570
[  133.684149]        bus_for_each_dev+0x145/0x1e0
[  133.686937]        driver_attach+0x49/0x60
[  133.689673]        bus_add_driver+0x2f3/0x6b0
[  133.692421]        driver_register+0x170/0x4b0
[  133.695118]        __dax_driver_register+0x141/0x1b0
[  133.697910]        dax_kmem_init+0x54/0xff0 [kmem]
[  133.700794]        do_one_initcall+0x117/0x5d0
[  133.703455]        do_init_module+0x277/0x750
[  133.706054]        load_module+0x5d1d/0x74f0
[  133.708602]        init_module_from_file+0x12c/0x1a0
[  133.711234]        idempotent_init_module+0x3f1/0x690
[  133.713937]        __x64_sys_finit_module+0x10e/0x1a0
[  133.716492]        x64_sys_call+0x184d/0x20d0
[  133.719053]        do_syscall_64+0x6d/0x140
[  133.721537]        entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  133.724239]
[  133.724239] other info that might help us debug this:
[  133.724239]
[  133.730832]  Possible unsafe locking scenario:
[  133.730832]
[  133.735298]        CPU0                    CPU1
[  133.737759]        ----                    ----
[  133.740165]   rlock((memory_chain).rwsem);
[  133.742623]                                lock(memory_tier_lock);
[  133.745357]                                lock((memory_chain).rwsem);
[  133.748141]   lock(memory_tier_lock);
[  133.750489]
[  133.750489]  *** DEADLOCK ***
[  133.750489]
[  133.756742] 6 locks held by (udev-worker)/1133:
[  133.759179]  #0: ffff888207be6158 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x26c/0x570
[  133.762299]  #1: ffffffff875b5868 (device_hotplug_lock){+.+.}-{3:3}, at: lock_device_hotplug+0x20/0x30
[  133.765565]  #2: ffff88820cf6a108 (&dev->mutex){....}-{3:3}, at: device_online+0x2f/0x1d0
[  133.768978]  #3: ffffffff86d08ff0 (cpu_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin+0x17/0x30
[  133.772312]  #4: ffffffff8702dfb0 (mem_hotplug_lock){++++}-{0:0}, at: mem_hotplug_begin+0x23/0x30
[  133.775544]  #5: ffffffff875d3310 ((memory_chain).rwsem){++++}-{3:3}, at: blocking_notifier_call_chain+0x60/0xb0
[  133.779113]
[  133.779113] stack backtrace:
[  133.783728] CPU: 5 UID: 0 PID: 1133 Comm: (udev-worker) Tainted: G           O     N 6.11.0-rc2+ #146
[  133.787220] Tainted: [O]=OOT_MODULE, [N]=TEST
[  133.789948] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
[  133.793291] Call Trace:
[  133.795826]  <TASK>
[  133.798284]  dump_stack_lvl+0xea/0x150
[  133.801025]  dump_stack+0x19/0x20
[  133.803609]  print_circular_bug+0x477/0x740
[  133.806341]  check_noncircular+0x2f4/0x3e0
[  133.809056]  ? __pfx_check_noncircular+0x10/0x10
[  133.811866]  ? __pfx_lockdep_lock+0x10/0x10
[  133.814670]  ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30
[  133.817610]  __lock_acquire+0x2efd/0x5c60
[  133.820339]  ? __pfx___lock_acquire+0x10/0x10
[  133.823128]  ? __dax_driver_register+0x141/0x1b0
[  133.825926]  ? do_one_initcall+0x117/0x5d0
[  133.828648]  lock_acquire+0x1ce/0x580
[  133.831349]  ? memtier_hotplug_callback+0x383/0x4b0
[  133.834293]  ? __pfx_lock_acquire+0x10/0x10
[  133.837134]  __mutex_lock+0x15c/0x1490
[  133.839829]  ? memtier_hotplug_callback+0x383/0x4b0
[  133.842753]  ? memtier_hotplug_callback+0x383/0x4b0
[  133.845602]  ? __this_cpu_preempt_check+0x21/0x30
[  133.848438]  ? __pfx___mutex_lock+0x10/0x10
[  133.851200]  ? __pfx_lock_acquire+0x10/0x10
[  133.853935]  ? global_dirty_limits+0xc0/0x160
[  133.856699]  ? __sanitizer_cov_trace_switch+0x58/0xa0
[  133.859564]  mutex_lock_nested+0x1f/0x30
[  133.862251]  ? mutex_lock_nested+0x1f/0x30
[  133.864964]  memtier_hotplug_callback+0x383/0x4b0
[  133.867752]  notifier_call_chain+0xbf/0x370
[  133.870550]  ? writeback_set_ratelimit+0xe8/0x160
[  133.873372]  blocking_notifier_call_chain+0x76/0xb0
[  133.876311]  memory_notify+0x2e/0x40
[  133.879013]  online_pages+0x597/0x720
[  133.881686]  ? irqentry_exit+0x3e/0xa0
[  133.884397]  ? __pfx_online_pages+0x10/0x10
[  133.887244]  ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30
[  133.890299]  ? mhp_init_memmap_on_memory+0x7a/0x1c0
[  133.893203]  memory_subsys_online+0x4f6/0x7f0
[  133.896099]  ? __pfx_memory_subsys_online+0x10/0x10
[  133.899039]  ? xa_load+0x16d/0x2e0
[  133.901667]  ? __pfx_xa_load+0x10/0x10
[  133.904366]  ? __pfx_memory_subsys_online+0x10/0x10
[  133.907218]  device_online+0x141/0x1d0
[  133.909845]  online_memory_block+0x4d/0x60
[  133.912494]  walk_memory_blocks+0xc0/0x120
[  133.915104]  ? __pfx_online_memory_block+0x10/0x10
[  133.917776]  add_memory_resource+0x51d/0x6c0
[  133.920404]  ? __pfx_add_memory_resource+0x10/0x10
[  133.923104]  ? _raw_write_unlock+0x31/0x60
[  133.925781]  ? register_memory_resource+0x119/0x180
[  133.928450]  add_memory_driver_managed+0xf5/0x180
[  133.931036]  dev_dax_kmem_probe+0x7f7/0xb40 [kmem]
[  133.933665]  ? __pfx_dev_dax_kmem_probe+0x10/0x10 [kmem]
[  133.936332]  ? __pfx___up_read+0x10/0x10
[  133.938878]  dax_bus_probe+0x147/0x230
[  133.941332]  ? __pfx_dax_bus_probe+0x10/0x10
[  133.943954]  really_probe+0x27f/0xac0
[  133.946387]  ? __sanitizer_cov_trace_const_cmp1+0x1e/0x30
[  133.949106]  __driver_probe_device+0x1f3/0x460
[  133.951704]  ? parse_option_str+0x149/0x190
[  133.954241]  driver_probe_device+0x56/0x1b0
[  133.956749]  __driver_attach+0x277/0x570
[  133.959228]  ? __pfx___driver_attach+0x10/0x10
[  133.961776]  bus_for_each_dev+0x145/0x1e0
[  133.964367]  ? __pfx_bus_for_each_dev+0x10/0x10
[  133.967019]  ? __kasan_check_read+0x15/0x20
[  133.969543]  ? _raw_spin_unlock+0x31/0x60
[  133.972132]  driver_attach+0x49/0x60
[  133.974536]  bus_add_driver+0x2f3/0x6b0
[  133.977044]  driver_register+0x170/0x4b0
[  133.979480]  __dax_driver_register+0x141/0x1b0
[  133.982126]  ? __pfx_dax_kmem_init+0x10/0x10 [kmem]
[  133.984724]  dax_kmem_init+0x54/0xff0 [kmem]
[  133.987284]  ? __pfx_dax_kmem_init+0x10/0x10 [kmem]
[  133.989965]  do_one_initcall+0x117/0x5d0
[  133.992506]  ? __pfx_do_one_initcall+0x10/0x10
[  133.995185]  ? __kasan_kmalloc+0x88/0xa0
[  133.997748]  ? kasan_poison+0x3e/0x60
[  134.000288]  ? kasan_unpoison+0x2c/0x60
[  134.002762]  ? kasan_poison+0x3e/0x60
[  134.005202]  ? __asan_register_globals+0x62/0x80
[  134.007753]  ? __pfx_dax_kmem_init+0x10/0x10 [kmem]
[  134.010439]  do_init_module+0x277/0x750
[  134.012953]  load_module+0x5d1d/0x74f0
[  134.015406]  ? __pfx_load_module+0x10/0x10
[  134.017887]  ? __pfx_ima_post_read_file+0x10/0x10
[  134.020470]  ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30
[  134.023127]  ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
[  134.025767]  ? security_kernel_post_read_file+0xa2/0xd0
[  134.028429]  ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
[  134.031162]  ? kernel_read_file+0x503/0x820
[  134.033645]  ? __pfx_kernel_read_file+0x10/0x10
[  134.036232]  ? __pfx___lock_acquire+0x10/0x10
[  134.038766]  init_module_from_file+0x12c/0x1a0
[  134.041291]  ? init_module_from_file+0x12c/0x1a0
[  134.043936]  ? __pfx_init_module_from_file+0x10/0x10
[  134.046516]  ? __this_cpu_preempt_check+0x21/0x30
[  134.049091]  ? __kasan_check_read+0x15/0x20
[  134.051551]  ? do_raw_spin_unlock+0x60/0x210
[  134.054077]  idempotent_init_module+0x3f1/0x690
[  134.056643]  ? __pfx_idempotent_init_module+0x10/0x10
[  134.059318]  ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
[  134.061995]  ? __fget_light+0x17d/0x210
[  134.064428]  __x64_sys_finit_module+0x10e/0x1a0
[  134.066976]  x64_sys_call+0x184d/0x20d0
[  134.069405]  do_syscall_64+0x6d/0x140
[  134.071926]  entry_SYSCALL_64_after_hwframe+0x76/0x7e

[yanfei.xu@intel.com: add mutex_lock/unlock() pair back]
  Link: https://lkml.kernel.org/r/20240830102447.1445296-1-yanfei.xu@intel.com
Link: https://lkml.kernel.org/r/20240827113614.1343049-1-yanfei.xu@intel.com
Fixes: 823430c ("memory tier: consolidate the initialization of memory tiers")
Signed-off-by: Yanfei Xu <yanfei.xu@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Ho-Ren (Jack) Chuang <horen.chuang@linux.dev>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
Patch series "zram: introduce custom comp backends API", v7.

This series introduces support for run-time compression algorithms tuning,
so users, for instance, can adjust compression/acceleration levels and
provide pre-trained compression/decompression dictionaries which certain
algorithms support.

At this point we stop supporting (old/deprecated) comp API.  We may add
new acomp API support in the future, but before that zram needs to undergo
some major rework (we are not ready for async compression).

Some benchmarks for reference (look at column #2)

*** init zstd
/sys/block/zram0/mm_stat
1750659072 504622188 514355200        0 514355200        1        0    34204    34204

*** init zstd dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750650880 465908890 475398144        0 475398144        1        0    34185    34185

*** init zstd level=8 dict=/home/ss/zstd-dict-amd64
/sys/block/zram0/mm_stat
1750654976 430803319 439873536        0 439873536        1        0    34185    34185

*** init lz4
/sys/block/zram0/mm_stat
1750646784 664266564 677060608        0 677060608        1        0    34288    34288

*** init lz4 dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750650880 619990300 632102912        0 632102912        1        0    34278    34278

*** init lz4hc
/sys/block/zram0/mm_stat
1750630400 609023822 621232128        0 621232128        1        0    34288    34288

*** init lz4hc dict=/home/ss/lz4-dict-amd64
/sys/block/zram0/mm_stat
1750659072 505133172 515231744        0 515231744        1        0    34278    34278


Recompress
init zram zstd (prio=0), zstd level=5 (prio 1), zstd with dict (prio 2)

*** zstd
/sys/block/zram0/mm_stat
1750982656 504630584 514269184        0 514269184        1        0    34204    34204

*** idle recompress priority=1 (zstd level=5)
/sys/block/zram0/mm_stat
1750982656 488645601 525438976        0 514269184        1        0    34204    34204

*** idle recompress priority=2 (zstd dict)
/sys/block/zram0/mm_stat
1750982656 460869640 517914624        0 514269184        1        0    34185    34204


This patch (of 24):

We need to export a number of API functions that enable advanced zstd
usage - C/D dictionaries, dictionaries sharing between contexts, etc.

Link: https://lkml.kernel.org/r/20240902105656.1383858-1-senozhatsky@chromium.org
Link: https://lkml.kernel.org/r/20240902105656.1383858-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
frank-w pushed a commit that referenced this pull request Sep 23, 2024
Hou Tao says:

====================
The tiny patch set aims to fix two problems found during the development
of supporting dynptr key in hash table. Patch #1 fixes the missed
btf_record_free() when map creation fails and patch #2 fixes the missed
kfree() when there is no special field in the passed btf.
====================

Link: https://lore.kernel.org/r/20240912012845.3458483-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
frank-w pushed a commit that referenced this pull request Sep 30, 2024
The following calculation used in coalesced_mmio_has_room() to check
whether the ring buffer is full is wrong and results in premature exits if
the start of the valid entries is in the first half of the ring buffer.

  avail = (ring->first - last - 1) % KVM_COALESCED_MMIO_MAX;
  if (avail == 0)
	  /* full */

Because negative values are handled using two's complement, and KVM
computes the result as an unsigned value, the above will get a false
positive if "first < last" and the ring is half-full.

The above might have worked as expected in python for example:
  >>> (-86) % 170
  84

However it doesn't work the same way in C.

  printf("avail: %d\n", (-86) % 170);
  printf("avail: %u\n", (-86) % 170);
  printf("avail: %u\n", (-86u) % 170u);

Using gcc-11 these print:

  avail: -86
  avail: 4294967210
  avail: 0

For illustration purposes, given a 4-bit integer and a ring size of 0xA
(unsigned), 0xA == 0x1010 == -6, and thus (-6u % 0xA) == 0.

Fix the calculation and allow all but one entries in the buffer to be
used as originally intended.

Note, KVM's behavior is self-healing to some extent, as KVM will allow the
entire buffer to be used if ring->first is beyond the halfway point.  In
other words, in the unlikely scenario that a use case benefits from being
able to coalesce more than 86 entries at once, KVM will still provide such
behavior, sometimes.

Note #2, the % operator in C is not the modulo operator but the remainder
operator. Modulo and remainder operators differ with respect to negative
values.  But, the relevant values in KVM are all unsigned, so it's a moot
point in this case anyway.

Note #3, this is almost a pure revert of the buggy commit, plus a
READ_ONCE() to provide additional safety.  Thue buggy commit justified the
change with "it paves the way for making this function lockless", but it's
not at all clear what was intended, nor is there any evidence that the
buggy code was somehow safer.  (a) the fields in question were already
accessed locklessly, from the perspective that they could be modified by
userspace at any time, and (b) the lock guarding the ring itself was
changed, but never dropped, i.e. whatever lockless scheme (SRCU?) was
planned never landed.

Fixes: 105f8d4 ("KVM: Calculate available entries in coalesced mmio ring")
Signed-off-by: Ilias Stamatis <ilstam@amazon.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Link: https://lore.kernel.org/r/20240718193543.624039-2-ilstam@amazon.com
[sean: rework changelog to clarify behavior, call out weirdness of buggy commit]
Signed-off-by: Sean Christopherson <seanjc@google.com>
frank-w pushed a commit that referenced this pull request Sep 30, 2024
Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock
on x86 due to a chain of locks and SRCU synchronizations.  Translating the
below lockdep splat, CPU1 #6 will wait on CPU0 #1, CPU0 #8 will wait on
CPU2 #3, and CPU2 #7 will wait on CPU1 #4 (if there's a writer, due to the
fairness of r/w semaphores).

    CPU0                     CPU1                     CPU2
1   lock(&kvm->slots_lock);
2                                                     lock(&vcpu->mutex);
3                                                     lock(&kvm->srcu);
4                            lock(cpu_hotplug_lock);
5                            lock(kvm_lock);
6                            lock(&kvm->slots_lock);
7                                                     lock(cpu_hotplug_lock);
8   sync(&kvm->srcu);

Note, there are likely more potential deadlocks in KVM x86, e.g. the same
pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with
__kvmclock_cpufreq_notifier():

  cpuhp_cpufreq_online()
  |
  -> cpufreq_online()
     |
     -> cpufreq_gov_performance_limits()
        |
        -> __cpufreq_driver_target()
           |
           -> __target_index()
              |
              -> cpufreq_freq_transition_begin()
                 |
                 -> cpufreq_notify_transition()
                    |
                    -> ... __kvmclock_cpufreq_notifier()

But, actually triggering such deadlocks is beyond rare due to the
combination of dependencies and timings involved.  E.g. the cpufreq
notifier is only used on older CPUs without a constant TSC, mucking with
the NX hugepage mitigation while VMs are running is very uncommon, and
doing so while also onlining/offlining a CPU (necessary to generate
contention on cpu_hotplug_lock) would be even more unusual.

The most robust solution to the general cpu_hotplug_lock issue is likely
to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq
notifier doesn't to take kvm_lock.  For now, settle for fixing the most
blatant deadlock, as switching to an RCU-protected list is a much more
involved change, but add a comment in locking.rst to call out that care
needs to be taken when walking holding kvm_lock and walking vm_list.

  ======================================================
  WARNING: possible circular locking dependency detected
  6.10.0-smp--c257535a0c9d-pip #330 Tainted: G S         O
  ------------------------------------------------------
  tee/35048 is trying to acquire lock:
  ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm]

  but task is already holding lock:
  ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm]

  which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

  -> #3 (kvm_lock){+.+.}-{3:3}:
         __mutex_lock+0x6a/0xb40
         mutex_lock_nested+0x1f/0x30
         kvm_dev_ioctl+0x4fb/0xe50 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #2 (cpu_hotplug_lock){++++}-{0:0}:
         cpus_read_lock+0x2e/0xb0
         static_key_slow_inc+0x16/0x30
         kvm_lapic_set_base+0x6a/0x1c0 [kvm]
         kvm_set_apic_base+0x8f/0xe0 [kvm]
         kvm_set_msr_common+0x9ae/0xf80 [kvm]
         vmx_set_msr+0xa54/0xbe0 [kvm_intel]
         __kvm_set_msr+0xb6/0x1a0 [kvm]
         kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm]
         kvm_vcpu_ioctl+0x485/0x5b0 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #1 (&kvm->srcu){.+.+}-{0:0}:
         __synchronize_srcu+0x44/0x1a0
         synchronize_srcu_expedited+0x21/0x30
         kvm_swap_active_memslots+0x110/0x1c0 [kvm]
         kvm_set_memslot+0x360/0x620 [kvm]
         __kvm_set_memory_region+0x27b/0x300 [kvm]
         kvm_vm_ioctl_set_memory_region+0x43/0x60 [kvm]
         kvm_vm_ioctl+0x295/0x650 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #0 (&kvm->slots_lock){+.+.}-{3:3}:
         __lock_acquire+0x15ef/0x2e30
         lock_acquire+0xe0/0x260
         __mutex_lock+0x6a/0xb40
         mutex_lock_nested+0x1f/0x30
         set_nx_huge_pages+0x179/0x1e0 [kvm]
         param_attr_store+0x93/0x100
         module_attr_store+0x22/0x40
         sysfs_kf_write+0x81/0xb0
         kernfs_fop_write_iter+0x133/0x1d0
         vfs_write+0x28d/0x380
         ksys_write+0x70/0xe0
         __x64_sys_write+0x1f/0x30
         x64_sys_call+0x281b/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

Cc: Chao Gao <chao.gao@intel.com>
Fixes: 0bf5049 ("KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock")
Cc: stable@vger.kernel.org
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240830043600.127750-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
BtbN pushed a commit to BtbN/BPI-Router-Linux that referenced this pull request Oct 4, 2024
[ Upstream commit 1a0bd28 ]

Case frank-w#1:
SQLite App		GC Thread		Kworker		Shrinker
- f2fs_ioc_start_atomic_write

- f2fs_ioc_commit_atomic_write
 - f2fs_commit_atomic_write
  - filemap_write_and_wait_range
  : write atomic_file's data to cow_inode
								echo 3 > drop_caches
								to drop atomic_file's
								cache.
			- f2fs_gc
			 - gc_data_segment
			  - move_data_page
			   - set_page_dirty

						- writepages
						 - f2fs_do_write_data_page
						 : overwrite atomic_file's data
						   to cow_inode
  - f2fs_down_write(&fi->i_gc_rwsem[WRITE])
  - __f2fs_commit_atomic_write
  - f2fs_up_write(&fi->i_gc_rwsem[WRITE])

Case frank-w#2:
SQLite App		GC Thread		Kworker
- f2fs_ioc_start_atomic_write

						- __writeback_single_inode
						 - do_writepages
						  - f2fs_write_cache_pages
						   - f2fs_write_single_data_page
						    - f2fs_do_write_data_page
						    : write atomic_file's data to cow_inode
			- f2fs_gc
			 - gc_data_segment
			  - move_data_page
			   - set_page_dirty

						- writepages
						 - f2fs_do_write_data_page
						 : overwrite atomic_file's data to cow_inode
- f2fs_ioc_commit_atomic_write

In above cases racing in between atomic_write and GC, previous
data in atomic_file may be overwrited to cow_file, result in
data corruption.

This patch introduces PAGE_PRIVATE_ATOMIC_WRITE bit flag in page.private,
and use it to indicate that there is last dirty data in atomic file,
and the data should be writebacked into cow_file, if the flag is not
tagged in page, we should never write data across files.

Fixes: 3db1de0 ("f2fs: change the current atomic write way")
Cc: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
BtbN pushed a commit to BtbN/BPI-Router-Linux that referenced this pull request Oct 4, 2024
commit 44d1745 upstream.

Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock
on x86 due to a chain of locks and SRCU synchronizations.  Translating the
below lockdep splat, CPU1 frank-w#6 will wait on CPU0 frank-w#1, CPU0 frank-w#8 will wait on
CPU2 frank-w#3, and CPU2 frank-w#7 will wait on CPU1 frank-w#4 (if there's a writer, due to the
fairness of r/w semaphores).

    CPU0                     CPU1                     CPU2
1   lock(&kvm->slots_lock);
2                                                     lock(&vcpu->mutex);
3                                                     lock(&kvm->srcu);
4                            lock(cpu_hotplug_lock);
5                            lock(kvm_lock);
6                            lock(&kvm->slots_lock);
7                                                     lock(cpu_hotplug_lock);
8   sync(&kvm->srcu);

Note, there are likely more potential deadlocks in KVM x86, e.g. the same
pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with
__kvmclock_cpufreq_notifier():

  cpuhp_cpufreq_online()
  |
  -> cpufreq_online()
     |
     -> cpufreq_gov_performance_limits()
        |
        -> __cpufreq_driver_target()
           |
           -> __target_index()
              |
              -> cpufreq_freq_transition_begin()
                 |
                 -> cpufreq_notify_transition()
                    |
                    -> ... __kvmclock_cpufreq_notifier()

But, actually triggering such deadlocks is beyond rare due to the
combination of dependencies and timings involved.  E.g. the cpufreq
notifier is only used on older CPUs without a constant TSC, mucking with
the NX hugepage mitigation while VMs are running is very uncommon, and
doing so while also onlining/offlining a CPU (necessary to generate
contention on cpu_hotplug_lock) would be even more unusual.

The most robust solution to the general cpu_hotplug_lock issue is likely
to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq
notifier doesn't to take kvm_lock.  For now, settle for fixing the most
blatant deadlock, as switching to an RCU-protected list is a much more
involved change, but add a comment in locking.rst to call out that care
needs to be taken when walking holding kvm_lock and walking vm_list.

  ======================================================
  WARNING: possible circular locking dependency detected
  6.10.0-smp--c257535a0c9d-pip #330 Tainted: G S         O
  ------------------------------------------------------
  tee/35048 is trying to acquire lock:
  ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm]

  but task is already holding lock:
  ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm]

  which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

  -> frank-w#3 (kvm_lock){+.+.}-{3:3}:
         __mutex_lock+0x6a/0xb40
         mutex_lock_nested+0x1f/0x30
         kvm_dev_ioctl+0x4fb/0xe50 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> frank-w#2 (cpu_hotplug_lock){++++}-{0:0}:
         cpus_read_lock+0x2e/0xb0
         static_key_slow_inc+0x16/0x30
         kvm_lapic_set_base+0x6a/0x1c0 [kvm]
         kvm_set_apic_base+0x8f/0xe0 [kvm]
         kvm_set_msr_common+0x9ae/0xf80 [kvm]
         vmx_set_msr+0xa54/0xbe0 [kvm_intel]
         __kvm_set_msr+0xb6/0x1a0 [kvm]
         kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm]
         kvm_vcpu_ioctl+0x485/0x5b0 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> frank-w#1 (&kvm->srcu){.+.+}-{0:0}:
         __synchronize_srcu+0x44/0x1a0
         synchronize_srcu_expedited+0x21/0x30
         kvm_swap_active_memslots+0x110/0x1c0 [kvm]
         kvm_set_memslot+0x360/0x620 [kvm]
         __kvm_set_memory_region+0x27b/0x300 [kvm]
         kvm_vm_ioctl_set_memory_region+0x43/0x60 [kvm]
         kvm_vm_ioctl+0x295/0x650 [kvm]
         __se_sys_ioctl+0x7b/0xd0
         __x64_sys_ioctl+0x21/0x30
         x64_sys_call+0x15d0/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

  -> #0 (&kvm->slots_lock){+.+.}-{3:3}:
         __lock_acquire+0x15ef/0x2e30
         lock_acquire+0xe0/0x260
         __mutex_lock+0x6a/0xb40
         mutex_lock_nested+0x1f/0x30
         set_nx_huge_pages+0x179/0x1e0 [kvm]
         param_attr_store+0x93/0x100
         module_attr_store+0x22/0x40
         sysfs_kf_write+0x81/0xb0
         kernfs_fop_write_iter+0x133/0x1d0
         vfs_write+0x28d/0x380
         ksys_write+0x70/0xe0
         __x64_sys_write+0x1f/0x30
         x64_sys_call+0x281b/0x2e60
         do_syscall_64+0x83/0x160
         entry_SYSCALL_64_after_hwframe+0x76/0x7e

Cc: Chao Gao <chao.gao@intel.com>
Fixes: 0bf5049 ("KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock")
Cc: stable@vger.kernel.org
Reviewed-by: Kai Huang <kai.huang@intel.com>
Acked-by: Kai Huang <kai.huang@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20240830043600.127750-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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