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ext4: drain in-flight DIO before buffered write fallback

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: ext4: drain in-flight DIO before buffered write fallback generic/746 started failing intermittently on ext3 (no-extent inodes). The test triggers 'Page cache invalidation failure on direct I/O' warnings and subsequent fsync returns -EIO. Adding a 50ms delay between ext4_buffered_write_iter() and filemap_write_and_wait_range() in ext4_dio_write_iter() makes the race almost always reproducible. On no-extent inodes, DIO writes to holes cannot use unwritten extents, so ext4_iomap_alloc() leaves m_flags=0 and ext4_map_blocks() returns 0. The iomap layer then returns -ENOTBLK, causing fallback to buffered I/O. The fallback path in ext4_dio_write_iter() calls ext4_buffered_write_iter() which dirties pages, then does flush and invalidate. However, there's an unprotected window between ext4_buffered_write_iter() returning (with inode lock released) and the subsequent flush+invalidate. Concurrent async DIO completions from other threads can run kiocb_invalidate_post_direct_write() during this window. If pages have been re-dirtied, post-invalidation finds dirty pages and triggers the warning, setting -EIO in the error sequence. Consider a file with two 4k extents: [hole][written]. Thread A does DIO to the written extent, while thread B does DIO spanning both: kworker A (4k DIO, allocated block) kworker B (8k DIO, fallback) ----------------------------------- ---------------------------- inode_lock_shared() inode_lock_sh

Announced Source revision 1
Original source ↗

CVE-2026-92501

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-2026-92501

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": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "fd7e0dab20837b9ea1eeef7c26f78ace8ac8258c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "f0af3ae09fb72382da1a5371bf6761b0264668e4",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "7341e234927ff215f1d5d0bcfe04b74f53af378d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "74eee4ff9698a65b2e6e15dac0e50d6526ad5f20",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "d47cdadd6e49023f7ee248048463807f1214f1ee",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "4e4e3eec506247c8f8bd8aaa1eb25e67016681a5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "9fd3ffc3c51c9deaba99bd7b338fff2d08f52416",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "378f32bab3714f04c4e0c3aee4129f6703805550",
        "lessThan": "15cdefd0c0522f9d5e12d947fa04f4c11649b699",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "fs/ext4/file.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.5"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.5",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.270",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "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/file.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-92501

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#37733 · Revision 1
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