---
id: CVE-2026-23419
title: 'net/rds: Fix circular locking dependency in rds_tcp_tune'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/rds: Fix circular locking dependency in rds_tcp_tune

  syzbot reported a circular locking dependency in rds_tcp_tune() where
  sk_net_refcnt_upgrade() is called while …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    ce5be6703afd2ac2ff7dabd397137d71d22d4bc3
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    8babb271403378ba6836f6c8599c5313d0e2355d
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    8519e6883a942e510f33a0e634e27bcc3a844a40
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    6ce948fa54599f369ff7fe8b793a6aae4b0762b2
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    026bbaeeab9e04534ee58882b6447300629b42f6
  - >-
    Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a <
    6a877ececd6daa002a9a0002cd0fbca6592a9244
  - Linux 2a6efabed754c9dcf27e6def71317b374f58a852
  - Linux >= 5.17.7 < 5.18
  - Linux 5.18
published: '2026-04-03'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:24:06.599Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-23419'
references:
  - url: 'https://git.kernel.org/stable/c/ce5be6703afd2ac2ff7dabd397137d71d22d4bc3'
  - url: 'https://git.kernel.org/stable/c/8babb271403378ba6836f6c8599c5313d0e2355d'
  - url: 'https://git.kernel.org/stable/c/8519e6883a942e510f33a0e634e27bcc3a844a40'
  - url: 'https://git.kernel.org/stable/c/6ce948fa54599f369ff7fe8b793a6aae4b0762b2'
  - url: 'https://git.kernel.org/stable/c/026bbaeeab9e04534ee58882b6447300629b42f6'
  - url: 'https://git.kernel.org/stable/c/6a877ececd6daa002a9a0002cd0fbca6592a9244'
tags:
  - cve.org
epss: 0.00193
epssPercentile: 0.09075
ingestedAt: '2026-11-05T15:02:32.208Z'
---

## Overview

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

net/rds: Fix circular locking dependency in rds_tcp_tune

syzbot reported a circular locking dependency in rds_tcp_tune() where
sk_net_refcnt_upgrade() is called while holding the socket lock:

======================================================
WARNING: possible circular locking dependency detected
======================================================
kworker/u10:8/15040 is trying to acquire lock:
ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0},
at: __kmalloc_cache_noprof+0x4b/0x6f0

but task is already holding lock:
ffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0},
at: rds_tcp_tune+0xd7/0x930

The issue occurs because sk_net_refcnt_upgrade() performs memory
allocation (via get_net_track() -> ref_tracker_alloc()) while the
socket lock is held, creating a circular dependency with fs_reclaim.

Fix this by moving sk_net_refcnt_upgrade() outside the socket lock
critical section. This is safe because the fields modified by the
sk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not
accessed by any concurrent code path at this point.

v2:
  - Corrected fixes tag
  - check patch line wrap nits
  - ai commentary nits

## Affected

- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < ce5be6703afd2ac2ff7dabd397137d71d22d4bc3`
- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < 8babb271403378ba6836f6c8599c5313d0e2355d`
- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < 8519e6883a942e510f33a0e634e27bcc3a844a40`
- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < 6ce948fa54599f369ff7fe8b793a6aae4b0762b2`
- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < 026bbaeeab9e04534ee58882b6447300629b42f6`
- `Linux >= 3a58f13a881ed351198ffab4cf9953cf19d2ab3a < 6a877ececd6daa002a9a0002cd0fbca6592a9244`
- `Linux 2a6efabed754c9dcf27e6def71317b374f58a852`
- `Linux >= 5.17.7 < 5.18`
- `Linux 5.18`

## Remediation

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