---
id: CVE-2026-90081
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/rds: use wq_has_sleeper() in rds_cong_map_updated()

  rds_cong_map_updated() runs after a peer's congestion map has been
  rewritten (by rds_tcp_cong_recv() and rds_ib…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/rds: use wq_has_sleeper() in rds_cong_map_updated()

  rds_cong_map_updated() runs after a peer's congestion map has been
  rewritten (by rds_tcp_cong_recv() and rds_ib…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    2a809d7896dbf18e1ecfbdd930f71c9fc298b16d
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    fa4b98e891fda28cc0638d809c6125ec63d8319d
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    0e169f6a2adeb17b5577ed7e8abd642465bb50ec
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    42884bd8b8fd023d6a610a695bd5ddd1d5dece17
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    a526214b9f0548ca0e53a6e0d1727d8ea9befc23
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    281f9fda2e06d6c211bb365a5379ed2e05cc2e21
  - >-
    Linux >= 922cb17a5c812fcc9ebee249f4109db099896941 <
    d4f484661961636eb90d287050959e613795f73a
  - Linux 2.6.30
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:16:57.423'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90081'
references:
  - url: 'https://git.kernel.org/stable/c/0e169f6a2adeb17b5577ed7e8abd642465bb50ec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/281f9fda2e06d6c211bb365a5379ed2e05cc2e21'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2a809d7896dbf18e1ecfbdd930f71c9fc298b16d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/42884bd8b8fd023d6a610a695bd5ddd1d5dece17'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a526214b9f0548ca0e53a6e0d1727d8ea9befc23'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bf2b8130723efcb5b86c3ddb6317c3a9b2a9cfc5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d4f484661961636eb90d287050959e613795f73a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fa4b98e891fda28cc0638d809c6125ec63d8319d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.895Z'
epss: 0.00211
epssPercentile: 0.11603
---

## Overview

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

net/rds: use wq_has_sleeper() in rds_cong_map_updated()

rds_cong_map_updated() runs after a peer's congestion map has been
rewritten (by rds_tcp_cong_recv() and rds_ib_cong_recv(), or the
clear-all in the loopback and IB send-completion paths).  It bumps
rds_cong_generation and then checks waitqueue_active() on
map->m_waitq and on rds_poll_waitq to decide whether anyone needs
waking.  atomic_inc() carries no ordering and waitqueue_active() is a
plain load, so nothing orders the map and generation stores before
the wait queue reads.  The waiters do the mirror image: rds_cong_wait()
adds itself to m_waitq and then tests the port bit, and rds_poll()
registers on rds_poll_waitq and then reads the generation.  That is
the store-buffering pattern described above waitqueue_active() in
include/linux/wait.h - the updater can observe an empty wait queue
while the waiter still observes the port as congested, and no wake-up
is issued.

rds_cong_wait() is an interruptible sleep with no timeout, so a
sender blocked on a congested port stays blocked until the next
congestion update from that peer arrives or a signal is delivered.
A poll() waiter misses the map-updated notification the same way.

Use wq_has_sleeper(), which is waitqueue_active() preceded by the
required full barrier, as rds_tcp_state_change() already does for
the same pattern.

## Remediation

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