Description
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@paragon-software.com: ni_readpage_cmpr was renamed to ni_read_folio_cmpr]
Product status
f35590ee26f5722bfe12cdff14396c4c057a8f74 (git) before cfe246b318106e1691bd6c9466c739e8559d25c2
f35590ee26f5722bfe12cdff14396c4c057a8f74 (git) before e37a75bb866c29da954b51d0dd7670406246d9ee
6.19
Any version before 6.19
6.19.4 (semver)
7.0 (original_commit_for_fix)
References
git.kernel.org/...c/cfe246b318106e1691bd6c9466c739e8559d25c2
git.kernel.org/...c/e37a75bb866c29da954b51d0dd7670406246d9ee