---
id: CVE-2026-89549
title: 'sunrpc: route to a populated pool in svc_pool_for_cpu()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  sunrpc: route to a populated pool in svc_pool_for_cpu()

  svc_set_num_threads() spreads the requested threads evenly across the
  service's pools (base = nrservs / sv_nrpo…
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 >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    9accc25e5af0bac8479f6054e674b2c593c45281
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    6f66d38e2a6c78d48723ea17ad86135ec80ca24b
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    d79d7b9e8acbb53e2d60f6b24afc13e2f15e691f
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    edb20e8c03aebacb409968c99d046f509c6c485a
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    011479cf9a7657d4a3e7cc42a784ac63df594170
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    9d04d64ad192439835ed9884d767353061c3ed6f
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    8f766d2d0b4dabf54f8b35812df2b4f481d13316
  - >-
    Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a <
    f6310491c4cdb88af73aa551ec9df1f10a90c709
  - Linux 2.6.19
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T12:00:52.566Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89549'
references:
  - url: 'https://git.kernel.org/stable/c/9accc25e5af0bac8479f6054e674b2c593c45281'
  - url: 'https://git.kernel.org/stable/c/6f66d38e2a6c78d48723ea17ad86135ec80ca24b'
  - url: 'https://git.kernel.org/stable/c/d79d7b9e8acbb53e2d60f6b24afc13e2f15e691f'
  - url: 'https://git.kernel.org/stable/c/edb20e8c03aebacb409968c99d046f509c6c485a'
  - url: 'https://git.kernel.org/stable/c/011479cf9a7657d4a3e7cc42a784ac63df594170'
  - url: 'https://git.kernel.org/stable/c/9d04d64ad192439835ed9884d767353061c3ed6f'
  - url: 'https://git.kernel.org/stable/c/8f766d2d0b4dabf54f8b35812df2b4f481d13316'
  - url: 'https://git.kernel.org/stable/c/f6310491c4cdb88af73aa551ec9df1f10a90c709'
tags:
  - cve.org
epss: 0.00716
epssPercentile: 0.51715
ingestedAt: '2026-09-14T15:23:07.452Z'
---

## Overview

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

sunrpc: route to a populated pool in svc_pool_for_cpu()

svc_set_num_threads() spreads the requested threads evenly across the
service's pools (base = nrservs / sv_nrpools).  When a service runs
fewer threads than it has pools -- e.g. an nfsd configured with fewer
threads than the host has NUMA nodes while running in "pernode" or
"percpu" mode -- the trailing pools are left with no threads at all.

svc_xprt_enqueue() selects a pool from the CPU servicing the transport,
queues the transport on that pool's sp_xprts, and only wakes a thread
from the same pool.  Each thread services exclusively its own pool, so a
transport that lands on a threadless pool is enqueued on sp_xprts and
never picked up: the connection hangs indefinitely.

Have svc_pool_for_cpu() skip pools that currently have no threads,
falling back to the next populated pool.  This trades NUMA locality for
a guarantee that the work is actually serviced.  sp_nrthreads is only
updated under the service mutex; the lockless read here is a best-effort
routing hint, so annotate it with data_race().

## Affected

- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < 9accc25e5af0bac8479f6054e674b2c593c45281`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < 6f66d38e2a6c78d48723ea17ad86135ec80ca24b`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < d79d7b9e8acbb53e2d60f6b24afc13e2f15e691f`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < edb20e8c03aebacb409968c99d046f509c6c485a`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < 011479cf9a7657d4a3e7cc42a784ac63df594170`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < 9d04d64ad192439835ed9884d767353061c3ed6f`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < 8f766d2d0b4dabf54f8b35812df2b4f481d13316`
- `Linux >= bfd241600a3b0db4fe43c859f1460d0a958d924a < f6310491c4cdb88af73aa551ec9df1f10a90c709`
- `Linux 2.6.19`

## Remediation

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