Subject: CVE-2022-48858: net/mlx5: Fix a race on command flush flow

From: Greg Kroah-Hartman <[email-masked]>

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

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

net/mlx5: Fix a race on command flush flow

Fix a refcount use after free warning due to a race on command entry.
Such race occurs when one of the commands releases its last refcount and
frees its index and entry while another process running command flush
flow takes refcount to this command entry. The process which handles
commands flush may see this command as needed to be flushed if the other
process released its refcount but didn't release the index yet. Fix it
by adding the needed spin lock.

It fixes the following warning trace:

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 11 PID: 540311 at lib/refcount.c:25 refcount_warn_saturate+0x80/0xe0
...
RIP: 0010:refcount_warn_saturate+0x80/0xe0
...
Call Trace:
 <TASK>
 mlx5_cmd_trigger_completions+0x293/0x340 [mlx5_core]
 mlx5_cmd_flush+0x3a/0xf0 [mlx5_core]
 enter_error_state+0x44/0x80 [mlx5_core]
 mlx5_fw_fatal_reporter_err_work+0x37/0xe0 [mlx5_core]
 process_one_work+0x1be/0x390
 worker_thread+0x4d/0x3d0
 ? rescuer_thread+0x350/0x350
 kthread+0x141/0x160
 ? set_kthread_struct+0x40/0x40
 ret_from_fork+0x1f/0x30
 </TASK>

The Linux kernel CVE team has assigned CVE-2022-48858 to this issue.

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

	Issue introduced in 5.4.71 with commit 073fff810206 and fixed in 5.4.185 with commit 1a4017926eee
	Issue introduced in 5.9 with commit 50b2412b7e78 and fixed in 5.10.106 with commit f3331bc17449
	Issue introduced in 5.9 with commit 50b2412b7e78 and fixed in 5.15.29 with commit 7c519f769f55
	Issue introduced in 5.9 with commit 50b2412b7e78 and fixed in 5.16.15 with commit 0401bfb27a91
	Issue introduced in 5.9 with commit 50b2412b7e78 and fixed in 5.17 with commit 063bd3555954
	Issue introduced in 5.8.15 with commit da87ea137373

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-2022-48858
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:
	drivers/net/ethernet/mellanox/mlx5/core/cmd.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/1a4017926eeea56c7540cc41b42106746ee8a0ee
	https://git.kernel.org/stable/c/f3331bc17449f15832c31823f27573f4c0e13e5f
	https://git.kernel.org/stable/c/7c519f769f555ff7d9d4ccba3497bbb589df360a
	https://git.kernel.org/stable/c/0401bfb27a91d7bdd74b1635c1aae57cbb128da6
	https://git.kernel.org/stable/c/063bd355595428750803d8736a9bb7c8db67d42d