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ext4: fix ABBA deadlock in ext4_xattr_inode_cache_find()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ext4: fix ABBA deadlock in ext4_xattr_inode_cache_find() Syzbot/stress-ng reported an ABBA deadlock in ext4 when exercising concurrent xattr workloads (using the ea_inode mount/format option). The deadlock occurs between the running transaction and the eviction thread: - Task 1 (stress-ng): Holds a reference to a shared mbcache_entry (ce) and calls ext4_xattr_inode_cache_find() -> ext4_iget() to retrieve the corresponding EA inode. Since the EA inode is currently being evicted, ext4_iget() blocks in __wait_on_freeing_inode() waiting for eviction to complete. - Task 2 (eviction thread): Currently evicting the same EA inode in ext4_evict_ea_inode(). It calls mb_cache_entry_wait_unused(oe) which blocks waiting for Task 1 to release the reference to the mbcache_entry. To break this deadlock, implement a new ext4_iget() configuration flag named EXT4_IGET_NOWAIT. When set, perform a non-blocking lookup of the inode via VFS's find_inode_nowait() API. If the inode is currently being evicted (marked with I_FREEING or I_WILL_FREE) or created (I_CREATING), or if it is not present in the VFS inode cache (cache miss), simply skip it (returning -ENOENT) rather than waiting for eviction/creation to complete, breaking the ABBA cycle. Since we return -ENOENT immediately on a cache miss, we never attempt to allocate a new inode or call iget_locked(), completely eliminating any TOCTOU race window. If the returned inode is I_NEW

Announced Group revision 1
Original source ↗

CVE-2026-92503

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-2026-92503

Linux

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

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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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": "737fb7853acd5bc8984f6f42e4bfba3334be8ae1",
        "lessThan": "29a2a166450a3e89f61a486033b10cf170fde8b0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0a46ef234756dca04623b7591e8ebb3440622f0b",
        "lessThan": "d3b19b318e0e0483180d15f1d9f5e807a1fb59d5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0a46ef234756dca04623b7591e8ebb3440622f0b",
        "lessThan": "074d0620401974cbfa9b63684cdfae99c7b2059c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0a46ef234756dca04623b7591e8ebb3440622f0b",
        "lessThan": "7720fddd1fe344d14be258a2028f74ebf1569511",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0a46ef234756dca04623b7591e8ebb3440622f0b",
        "lessThan": "03438084a7b8621fb5c762dd3d04cff5f2630fb2",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0752e7fb549d90c33b4d4186f11cfd25a556d1dd",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "111103907234bffd0a34fba070ad9367de058752",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.6.47",
        "lessThan": "6.6.160",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.107",
        "lessThan": "6.2",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.9.7",
        "lessThan": "6.10",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "fs/ext4/ext4.h",
      "fs/ext4/inode.c",
      "fs/ext4/xattr.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.114",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.57",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "fs/ext4/ext4.h",
      "fs/ext4/inode.c",
      "fs/ext4/xattr.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-92503

Source reference: /cveMetadata/cveId

Publisher severity

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Event
#48702 · Revision 1
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Publisher date
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Revision history

  1. CVE-2026-92503 · Revision 1Source updated