CVE-2026-80739

/// Technical description

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

_

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References