linux-cve-announce - CVE-2022-50166: Bluetooth: When HCI work queue is drained, only queue chained work

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Message-ID: <2025061827-CVE-2022-50166-5ecc@gregkh>
Date: Wed, 18 Jun 2025 13:03:51 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50166: Bluetooth: When HCI work queue is drained, only queue chained work

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

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

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

Bluetooth: When HCI work queue is drained, only queue chained work

The HCI command, event, and data packet processing workqueue is drained
to avoid deadlock in commit
76727c02c1e1 ("Bluetooth: Call drain_workqueue() before resetting state").

There is another delayed work, which will queue command to this drained
workqueue. Which results in the following error report:

Bluetooth: hci2: command 0x040f tx timeout
WARNING: CPU: 1 PID: 18374 at kernel/workqueue.c:1438 __queue_work+0xdad/0x1140
Workqueue: events hci_cmd_timeout
RIP: 0010:__queue_work+0xdad/0x1140
RSP: 0000:ffffc90002cffc60 EFLAGS: 00010093
RAX: 0000000000000000 RBX: ffff8880b9d3ec00 RCX: 0000000000000000
RDX: ffff888024ba0000 RSI: ffffffff814e048d RDI: ffff8880b9d3ec08
RBP: 0000000000000008 R08: 0000000000000000 R09: 00000000b9d39700
R10: ffffffff814f73c6 R11: 0000000000000000 R12: ffff88807cce4c60
R13: 0000000000000000 R14: ffff8880796d8800 R15: ffff8880796d8800
FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c0174b4000 CR3: 000000007cae9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ? queue_work_on+0xcb/0x110
 ? lockdep_hardirqs_off+0x90/0xd0
 queue_work_on+0xee/0x110
 process_one_work+0x996/0x1610
 ? pwq_dec_nr_in_flight+0x2a0/0x2a0
 ? rwlock_bug.part.0+0x90/0x90
 ? _raw_spin_lock_irq+0x41/0x50
 worker_thread+0x665/0x1080
 ? process_one_work+0x1610/0x1610
 kthread+0x2e9/0x3a0
 ? kthread_complete_and_exit+0x40/0x40
 ret_from_fork+0x1f/0x30
 </TASK>

To fix this, we can add a new HCI_DRAIN_WQ flag, and don't queue the
timeout workqueue while command workqueue is draining.

The Linux kernel CVE team has assigned CVE-2022-50166 to this issue.


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

	Issue introduced in 3.19 with commit 76727c02c1e14a2b561b806fa1d08acc1619ad27 and fixed in 5.18.18 with commit 4bf367fa1fefabdf14938d0ac9ed60020389112e
	Issue introduced in 3.19 with commit 76727c02c1e14a2b561b806fa1d08acc1619ad27 and fixed in 5.19.2 with commit 3b382555706558f5c0587862b6dc03e96a252bba
	Issue introduced in 3.19 with commit 76727c02c1e14a2b561b806fa1d08acc1619ad27 and fixed in 6.0 with commit 877afadad2dce8aae1f2aad8ce47e072d4f6165e

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-2022-50166
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:
	include/net/bluetooth/hci.h
	net/bluetooth/hci_core.c
	net/bluetooth/hci_event.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/4bf367fa1fefabdf14938d0ac9ed60020389112e
	https://git.kernel.org/stable/c/3b382555706558f5c0587862b6dc03e96a252bba
	https://git.kernel.org/stable/c/877afadad2dce8aae1f2aad8ce47e072d4f6165e