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CVE PROGRAM SOURCE RECORD7.5 High

CVE-2026-72203

ntfs: skip extent mft records in writeback to prevent deadlock

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ntfs: skip extent mft records in writeback to prevent deadlock This patch fixes the ABBA deadlock between extent_lock and extent mrec_lock triggered by xfstests generic/113, that occurs since the commit 6994acf33bae ("ntfs: use base mft_no when looking up base inode for extent record"). Path A (inode writeback): VFS writeback -> ntfs_write_inode() -> __ntfs_write_inode() -> mutex_lock(&ni->extent_lock) -> mutex_lock(&tni->mrec_lock) Path B (MFT folio writeback): VFS writeback of $MFT dirty folios -> ntfs_mft_writepages() -> ntfs_write_mft_block() -> ntfs_may_write_mft_record() -> holds one extent mrec_lock from a previous iteration -> tries to acquire another base inode extent_lock By removing all extent_lock and extent mrec_lock acquisition from the MFT folio writeback path, the ABBA lock ordering is eliminated: Path A: __ntfs_write_inode(): extent_lock -> mrec_lock Path B (removed): ntfs_write_mft_block(): mrec_lock -> extent_lock Path B is always redundant for extent records because: 1. mark_mft_record_dirty(ext_ni) does NOT dirty the MFT folio. It only sets NInoDirty(ext_ni) and marks the base VFS inode dirty via __mark_inode_dirty(I_DIRTY_DATASYNC), which triggers Path A. Therefore, normal extent modifications never create a situation where the MFT folio is dirty and Path B is not scheduled. 2. The MFT folio only gets dirtied via ntfs_mft_mark_dirty() inside ntfs_mft_record_alloc(). But all identified callers in attrib.c (ntfs_attr_add, ntfs_attr_record_move_away, ntfs_attr_make_non_resident, ntfs_attr_record_resize) follow through with mark_mft_record_dirty(), which triggers Path A to write the complete record. 3. ntfs_evict_big_inode() calls ntfs_commit_inode() before freeing extent inodes, ensuring all dirty extents are flushed via Path A before the base inode leaves the icache.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < b06b4fc2138ded8ee0b3dc602991ff6dbb10dd0aaffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 6626fb859f4c4772f2f59751d23937716e03f98faffected
  • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to < 7ffa8f3d30236e0ab897c30bdb01224ff1fe1c89affected
  • 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 to < f831ab09d521898bf1dd99bf5adfd630ea1428e3affected
  • 1e9ea7e04472d4e5e12e58c881eaacfb3e49b669 to < 76bc14c7097ff678b2b5dbfd4fa33b46897d87ceaffected

Linux Linux

Default version status: affected

  • 2.6.12affected
  • 7.1affected
  • 0 to < 2.6.12unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.9 to < 7.1unaffected
  • 7.1.5 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References