CVE-2026-64122: net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover

CVE-2026-64122: net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover

[Greg Kroah-Hartman]

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

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

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

net/mlx5e: Fix use-after-free in mlx5e_tx_reporter_timeout_recover

mlx5e_tx_reporter_timeout_recover() accesses sq->netdev after
mlx5e_safe_reopen_channels() has torn down and freed the channel (and
its embedded SQs). Replace the three sq->netdev references with
priv->netdev which is safe because priv outlives channel teardown.

The netdev_err() call already used priv->netdev for this reason; make
the trylock/unlock and health_channel_eq_recover calls consistent.

This fixes the following KASAN splat:

  BUG: KASAN: use-after-free in mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core]
  Read of size 8 at addr ffff889860ed0b28 by task kworker/u113:2/5277

  Call Trace:
   mlx5e_tx_reporter_timeout_recover+0x1dd/0x360 [mlx5_core]
   devlink_health_reporter_recover+0xa2/0x150
   devlink_health_report+0x254/0x7c0
   mlx5e_reporter_tx_timeout+0x297/0x380 [mlx5_core]
   mlx5e_tx_timeout_work+0x109/0x170 [mlx5_core]
   process_one_work+0x677/0xf20
   worker_thread+0x51f/0xd90
   kthread+0x3a5/0x810
   ret_from_fork+0x208/0x400
   ret_from_fork_asm+0x1a/0x30

The Linux kernel CVE team has assigned CVE-2026-64122 to this issue.


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

	Issue introduced in 6.18.14 with commit 4329514c61abefe4961541b128c549b017bab5ad and fixed in 6.18.34 with commit 1604a2d68414aa4cc34faac0b7faa9c14455e8d3
	Issue introduced in 7.0 with commit 83ac0304a2d77519dae1e54c9713cbe1aedf19c9 and fixed in 7.0.11 with commit 152295aa7dc2c5e046606f7dadc84fce41136446
	Issue introduced in 7.0 with commit 83ac0304a2d77519dae1e54c9713cbe1aedf19c9 and fixed in 7.1 with commit 7d260c5d2d89eb2c8c528d54b576b3aae3e20231
	Issue introduced in 6.19.4 with commit 63f9d5fb4d8040077df801ca3270e2f02d55e0d9

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-2026-64122
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/en/reporter_tx.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/1604a2d68414aa4cc34faac0b7faa9c14455e8d3
	https://git.kernel.org/stable/c/152295aa7dc2c5e046606f7dadc84fce41136446
	https://git.kernel.org/stable/c/7d260c5d2d89eb2c8c528d54b576b3aae3e20231