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btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs() In the beginning of the loop, we try to obtain a locked delayed ref head, if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(), which can return an error pointer. If the error pointer is -EAGAIN we do a continue and go back to the beginning of the loop, which will not try again to call btrfs_select_ref_head() since 'locked_ref' is no longer NULL but it's ERR_PTR(-EAGAIN), and then we do: spin_lock(&locked_ref->lock); against a ERR_PTR(-EAGAIN) value, generating an invalid pointer dereference. Fix this by ensuring that 'locked_ref' is set to NULL when btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count' as well, to prevent infinite looping. We do this by doing a goto to the bottom of the loop that already sets 'locked_ref' to NULL and does a cond_resched(), with an increment to 'count' right before the goto. These measures were in place before the refactoring in commit 0110a4c43451 ("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally lost afterwards.

Announced Source revision 1
Original source ↗

CVE-2026-74321

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-2026-74321

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": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "c372ca227e16bace86f1df1fa4ae6849e2fcfa28",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "a71143590ce9764dbcb47617647592ff8b4d48bc",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "65770111a2d47c2b15e20b2ba92bb12198f289d4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "015dc4a1e0c2cba551d4620eba13d26d5081dc34",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "ba9fa2ff5981589bb49094d3358c339b37c47f53",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "9faa6b69ad73f03c7bde53e07d75a28822dc9a1a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0110a4c43451533de1ea1bbdc57b5d452f9d8b25",
        "lessThan": "486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/btrfs/extent-tree.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.20"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.20",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/btrfs/extent-tree.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74321

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#33097 · Revision 1
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Publisher date
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