---
id: CVE-2026-80739
title: 'net/mlx5e: TC, Check if flow is PEER before acquiring devcom lock'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/mlx5e: TC, Check if flow is PEER before acquiring devcom lock

  In case __mlx5e_add_fdb_flow() fails in lower levels, the flow is
  deleted via mlx5e_tc_del_flow(), an…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    ead5145d290a918b7c3c3141a64b3f827a9e1b6b
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    607adbda01053abf5f93e322fe39325da8828cb8
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    585df8643081e6f616579bc52cd49ac823a57c82
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    ff9e7d5e3500be389ce7a0e46db3a77149830bc9
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    7165fe321c61ec138850c02f030f274797761f5f
  - >-
    Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d <
    6ddfba2ea98db21b001e0e5c472499156224650c
  - Linux 5.0
published: '2026-09-03'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:31:03.271Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80739'
references:
  - url: 'https://git.kernel.org/stable/c/ead5145d290a918b7c3c3141a64b3f827a9e1b6b'
  - url: 'https://git.kernel.org/stable/c/607adbda01053abf5f93e322fe39325da8828cb8'
  - url: 'https://git.kernel.org/stable/c/585df8643081e6f616579bc52cd49ac823a57c82'
  - url: 'https://git.kernel.org/stable/c/ff9e7d5e3500be389ce7a0e46db3a77149830bc9'
  - url: 'https://git.kernel.org/stable/c/7165fe321c61ec138850c02f030f274797761f5f'
  - url: 'https://git.kernel.org/stable/c/6ddfba2ea98db21b001e0e5c472499156224650c'
tags:
  - cve.org
epss: 0.00173
epssPercentile: 0.06701
ingestedAt: '2026-11-05T15:02:32.610Z'
---

## Overview

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

net/mlx5e: TC, Check if flow is PEER before acquiring devcom lock

In case __mlx5e_add_fdb_flow() fails in lower levels, the flow is
deleted via mlx5e_tc_del_flow(), and mlx5e_tc_del_flow() is acquiring
ESW devcom lock without condition. In addition, in case of peer_flow,
__mlx5e_add_fdb_flow() is called while holding ESW devcom comp lock.
This results in an AA deadlock.

To fix this, introduce a new PEER flag that is set on flows created as
peer flows (the duplicate flows on peer devices), and check it in
mlx5e_tc_del_flow() before acquiring ESW devcom lock.

Lockdep splat:
============================================
WARNING: possible recursive locking detected
============================================
 Possible unsafe locking scenario:
       CPU0
       ----
  lock(&comp->lock_key#2);
  lock(&comp->lock_key#2);
 *** DEADLOCK ***
Call Trace:
 <TASK>
 dump_stack_lvl+0x69/0xa0
 print_deadlock_bug.cold+0xbd/0xca
 __lock_acquire+0x1671/0x2ec0
 lock_acquire+0x10e/0x2e0
 down_read+0x95/0x430
 mlx5_devcom_for_each_peer_begin+0x4e/0xe0 [mlx5_core]
 mlx5e_tc_del_flow+0x11d/0xa70 [mlx5_core]
 mlx5e_flow_put+0x99/0x100 [mlx5_core]
 __mlx5e_add_fdb_flow+0x409/0xf00 [mlx5_core]
 mlx5e_configure_flower+0x2a86/0x4100 [mlx5_core]
 mlx5e_rep_setup_tc_cls_flower+0x12f/0x1b0 [mlx5_core]
 mlx5e_rep_setup_tc_cb+0x153/0x750 [mlx5_core]
 tc_setup_cb_add+0x1dc/0x470
 fl_change+0x2f4d/0x626d [cls_flower]
 tc_new_tfilter+0x79b/0x2310
 rtnetlink_rcv_msg+0x778/0xad0
 do_syscall_64+0x70/0x960
 entry_SYSCALL_64_after_hwframe+0x4b/0x53
 </TASK>

## Affected

- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < ead5145d290a918b7c3c3141a64b3f827a9e1b6b`
- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < 607adbda01053abf5f93e322fe39325da8828cb8`
- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < 585df8643081e6f616579bc52cd49ac823a57c82`
- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < ff9e7d5e3500be389ce7a0e46db3a77149830bc9`
- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < 7165fe321c61ec138850c02f030f274797761f5f`
- `Linux >= 04de7dda7394fa9c2b0fc9cec65661d9b4f0d04d < 6ddfba2ea98db21b001e0e5c472499156224650c`
- `Linux 5.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.