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

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-74601

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-74601

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "26662bc8fced1d668fa1aa146eda085bfc67bd0b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "6b524e6b234e45c7f5f90d13b042c6f57f80105c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "597f279b7b4a06412e3d965e98cc36e181cdbede",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "22709117d9ae95e52673685f98caac7c356a8227",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "ad7e10c7ea89af45ac1bf1814855d45da472703d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "5b926fb04cb9ef3156dcf88c69a59d3d1a1c4f9f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "5e6e2a18c20e88167d414f666032792e8bf19b80",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "4239c38fe0b3847e1e6d962c74b41b08ba0e2990",
        "lessThan": "f27bdc43077e4fcb5557dfc315ee8d91e741f483",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "kernel/trace/ring_buffer.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.5"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.5",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.266",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.217",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.184",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.153",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.105",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.45",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/trace/ring_buffer.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74601

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#33233 · Revision 1
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Publisher date
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