---
id: CVE-2026-89748
title: 'tracing: Fix retry exhaustion in simple ring buffer reader swap'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tracing: Fix retry exhaustion in simple ring buffer reader swap

  simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
  post-decrements it only after a fa…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-787
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 <
    df02489aa3aa1834659f0d20c89f7d212047d268
  - >-
    Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 <
    e0d3aed7b12cf37b74c7cc5265073d0263b49cde
  - Linux 7.1
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:52:02.172Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89748'
references:
  - url: 'https://git.kernel.org/stable/c/df02489aa3aa1834659f0d20c89f7d212047d268'
  - url: 'https://git.kernel.org/stable/c/e0d3aed7b12cf37b74c7cc5265073d0263b49cde'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89748.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89748'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532233'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89748'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89748'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89748.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00165
epssPercentile: 0.05678
scores:
  cna: 7.8
  vendor: 5.5
ingestedAt: '2026-09-14T15:23:07.472Z'
---

## Overview

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

tracing: Fix retry exhaustion in simple ring buffer reader swap

simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
post-decrements it only after a failed link replacement. On the final
attempt, a successful replacement leaves retry at zero, while a failed
replacement leaves it at -1.

The current !retry test reverses both outcomes. It returns an error after
a successful final replacement, leaving the link update complete but the
reader bookkeeping unfinished. After a failed final replacement, it
falls through and updates the head and reader pointers as though the
replacement succeeded, which can corrupt the ring.

Treat only a negative counter as exhaustion and return the documented
-EBUSY error.

## Affected

- `Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < df02489aa3aa1834659f0d20c89f7d212047d268`
- `Linux >= 34e5b958bdad0f9cf16306368bbc2dc5b2a50143 < e0d3aed7b12cf37b74c7cc5265073d0263b49cde`
- `Linux 7.1`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89748.json)