---
id: CVE-2026-80866
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tipc: avoid busy looping in tipc_exit_net()

  Blamed commit introduced a busy-wait loop in tipc_exit_net()
  to wait for pending UDP bearer cleanup works to complete:

     …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tipc: avoid busy looping in tipc_exit_net()

  Blamed commit introduced a busy-wait loop in tipc_exit_net()
  to wait for pending UDP bearer cleanup works to complete:

     …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 04c26faa51d1e2fe71cf13c45791f5174c37f986 <
    7672973957e3e20780afe5937a9fec70b72bc060
  - >-
    Linux >= 04c26faa51d1e2fe71cf13c45791f5174c37f986 <
    522d1d950b9e3b68190a6de7534827c8dccedb73
  - >-
    Linux >= 04c26faa51d1e2fe71cf13c45791f5174c37f986 <
    c1481c94e74c955e0448ddf46b8615a44d840c1e
  - Linux d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa
  - Linux 5195ec5e365a2a9331bfeb585b613a6e94f98dba
  - Linux b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d
  - Linux >= 5.4.124 < 5.5
  - Linux >= 5.10.42 < 5.11
  - Linux >= 5.12.9 < 5.13
  - Linux 5.13
published: '2026-09-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:17:52.417'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80866'
references:
  - url: 'https://git.kernel.org/stable/c/522d1d950b9e3b68190a6de7534827c8dccedb73'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7672973957e3e20780afe5937a9fec70b72bc060'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c1481c94e74c955e0448ddf46b8615a44d840c1e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00198
epssPercentile: 0.08906
ingestedAt: '2026-10-15T11:00:41.661Z'
---

## Overview

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

tipc: avoid busy looping in tipc_exit_net()

Blamed commit introduced a busy-wait loop in tipc_exit_net()
to wait for pending UDP bearer cleanup works to complete:

       while (atomic_read(&tn->wq_count))
               cond_resched();

This loop can busy-wait for a long time if cond_resched() is a NOP. This
typically happens if the netns exit is executed by a high priority task,
or under kernels configured without preemption (CONFIG_PREEMPT_NONE). In
such cases, it wastes CPU cycles and can lead to soft lockups.

Fix this by replacing the busy loop with wait_var_event(), allowing the
thread to sleep properly until the work queue count reaches zero.

Accordingly, update cleanup_bearer() to use atomic_dec_and_test() and
wake_up_var() to wake up the waiter when the count drops to zero.

This uses the global wait queue hash table, avoiding the need to bloat
struct tipc_net with a wait_queue_head_t. The atomic_dec_and_test()
provides the necessary memory barrier to ensure the wakeup is not missed.

## Remediation

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