linux-cve-announce - CVE-2022-50705: io_uring/rw: defer fsnotify calls to task context

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Message-ID: <2025122419-CVE-2022-50705-8196@gregkh>
Date: Wed, 24 Dec 2025 11:56:22 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50705: io_uring/rw: defer fsnotify calls to task context

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

io_uring/rw: defer fsnotify calls to task context

We can't call these off the kiocb completion as that might be off
soft/hard irq context. Defer the calls to when we process the
task_work for this request. That avoids valid complaints like:

stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_usage_bug kernel/locking/lockdep.c:3961 [inline]
 valid_state kernel/locking/lockdep.c:3973 [inline]
 mark_lock_irq kernel/locking/lockdep.c:4176 [inline]
 mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632
 mark_lock kernel/locking/lockdep.c:4596 [inline]
 mark_usage kernel/locking/lockdep.c:4527 [inline]
 __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007
 lock_acquire kernel/locking/lockdep.c:5666 [inline]
 lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline]
 fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688
 might_alloc include/linux/sched/mm.h:271 [inline]
 slab_pre_alloc_hook mm/slab.h:700 [inline]
 slab_alloc mm/slab.c:3278 [inline]
 __kmem_cache_alloc_lru mm/slab.c:3471 [inline]
 kmem_cache_alloc+0x39/0x520 mm/slab.c:3491
 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline]
 fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline]
 fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948
 send_to_group fs/notify/fsnotify.c:360 [inline]
 fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570
 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230
 fsnotify_parent include/linux/fsnotify.h:77 [inline]
 fsnotify_file include/linux/fsnotify.h:99 [inline]
 fsnotify_access include/linux/fsnotify.h:309 [inline]
 __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195
 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228
 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline]
 iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178
 bio_endio+0x5f9/0x780 block/bio.c:1564
 req_bio_endio block/blk-mq.c:695 [inline]
 blk_update_request+0x3fc/0x1300 block/blk-mq.c:825
 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541
 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971
 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438
 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022
 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240

The Linux kernel CVE team has assigned CVE-2022-50705 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.15.54 with commit df1ec53252d5b5b26ea49e30438741c9a6d89857 and fixed in 5.15.90 with commit 89a410dbd0f159ddd308f19d6eb682fc753e4771
	Issue introduced in 5.18 with commit f63cf5192fe3418ad5ae1a4412eba5694b145f79 and fixed in 6.0.3 with commit 2a853c206e553dd9c0a55c22858fd6a446d93e15
	Issue introduced in 5.18 with commit f63cf5192fe3418ad5ae1a4412eba5694b145f79 and fixed in 6.1 with commit b000145e9907809406d8164c3b2b8861d95aecd1
	Issue introduced in 5.16.19 with commit dfbe550c8235b7e98284db37eeeddfd3b4b19b00
	Issue introduced in 5.17.2 with commit b436d1e92662adecafff4c95baae6352289c2d80

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-50705
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	io_uring/rw.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/89a410dbd0f159ddd308f19d6eb682fc753e4771
	https://git.kernel.org/stable/c/2a853c206e553dd9c0a55c22858fd6a446d93e15
	https://git.kernel.org/stable/c/b000145e9907809406d8164c3b2b8861d95aecd1