Bug 2482090 (CVE-2025-71309)

Summary: CVE-2025-71309 kernel: fs/ntfs3: fix deadlock in ni_read_folio_cmpr
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: unspecified    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's ntfs3 filesystem driver. An issue with incorrect lock ordering between the inode mutex and page locks during compressed frame reading can lead to a deadlock. This vulnerability allows a local attacker to cause a system to hang, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-05-27 15:10:50 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: fix deadlock in ni_read_folio_cmpr

Syzbot reported a task hung in ni_readpage_cmpr (now ni_read_folio_cmpr).
This is caused by a lock inversion deadlock involving the inode mutex
(ni_lock) and page locks.

Scenario:
1. Task A enters ntfs_read_folio() for page X. It acquires ni_lock.
2. Task A calls ni_read_folio_cmpr(), which attempts to lock all pages in
   the compressed frame (including page Y).
3. Concurrently, Task B (e.g., via readahead) has locked page Y and
   calls ntfs_read_folio().
4. Task B waits for ni_lock (held by A).
5. Task A waits for page Y lock (held by B).
   -> DEADLOCK.

The fix is to restructure locking: do not take ni_lock in ntfs_read_folio().
Instead, acquire ni_lock inside ni_read_folio_cmpr() ONLY AFTER all required
page locks for the frame have been successfully acquired. This restores the
correct lock ordering (Page Lock -> ni_lock) consistent with VFS.

[almaz.alexandrovich: ni_readpage_cmpr was renamed to ni_read_folio_cmpr]
Comment 1 Keith Grant 2026-05-28 20:14:23 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052707-CVE-2025-71309-9e3c@gregkh/T