---
id: CVE-2026-74601
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ring-buffer: Use current_context for safe per-CPU buffer swap

  The ring_buffer_swap_cpu() function currently checks the per-CPU
  committing counter to determine if a buf…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ring-buffer: Use current_context for safe per-CPU buffer swap

  The ring_buffer_swap_cpu() function currently checks the per-CPU
  committing counter to determine if a buf…
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'
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74601'
references:
  - url: 'https://git.kernel.org/stable/c/22709117d9ae95e52673685f98caac7c356a8227'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/26662bc8fced1d668fa1aa146eda085bfc67bd0b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/597f279b7b4a06412e3d965e98cc36e181cdbede'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5e6e2a18c20e88167d414f666032792e8bf19b80'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6b524e6b234e45c7f5f90d13b042c6f57f80105c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ad7e10c7ea89af45ac1bf1814855d45da472703d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f27bdc43077e4fcb5557dfc315ee8d91e741f483'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00136
epssPercentile: 0.02625
ingestedAt: '2026-10-14T13:30:58.512Z'
---

## Overview

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

ring-buffer: Use current_context for safe per-CPU buffer swap

The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:

    ring_buffer_lock_reserve
        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
        rb_reserve_next_event
            rb_start_commit // inc committing
            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
            __rb_reserve_next
                rb_move_tail
                    rb_end_commit(cpu_buffer);   // dec committing => 0
                    /* interrupt hits here, successfully swaps! */
                    local_inc(&cpu_buffer->committing);

    ring_buffer_unlock_commit
        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
        rb_commit
            rb_end_commit
            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                                // triggers warning

The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.

## Remediation

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