ocfs2: fix races between hole punching and AIO+DIO
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix races between hole punching and AIO+DIO After commit "ocfs2: return real error code in ocfs2_dio_wr_get_block", fstests/generic/300 become from always failed to sometimes failed: ======================================================================== [ 473.293420 ] run fstests generic/300 [ 475.296983 ] JBD2: Ignoring recovery information on journal [ 475.302473 ] ocfs2: Mounting device (253,1) on (node local, slot 0) with ordered data mode. [ 494.290998 ] OCFS2: ERROR (device dm-1): ocfs2_change_extent_flag: Owner 5668 has an extent at cpos 78723 which can no longer be found [ 494.291609 ] On-disk corruption discovered. Please run fsck.ocfs2 once the filesystem is unmounted. [ 494.292018 ] OCFS2: File system is now read-only. [ 494.292224 ] (kworker/19:11,2628,19):ocfs2_mark_extent_written:5272 ERROR: status = -30 [ 494.292602 ] (kworker/19:11,2628,19):ocfs2_dio_end_io_write:2374 ERROR: status = -3 fio: io_u error on file /mnt/scratch/racer: Read-only file system: write offset=460849152, buflen=131072 ========================================================================= In __blockdev_direct_IO, ocfs2_dio_wr_get_block is called to add unwritten extents to a list. extents are also inserted into extent tree in ocfs2_write_begin_nolock. Then another thread call fallocate to puch a hole at one of the unwritten extent. The extent at cpos was removed by ocfs2_remove_extent(). At end io worker thread, ocfs2_search_extent_list found there is no such extent at the cpos. T1 T2 T3 inode lock ... insert extents ... inode unlock ocfs2_fallocate __ocfs2_change_file_space inode lock lock ip_alloc_sem ocfs2_remove_inode_range inode ocfs2_remove_btree_range ocfs2_remove_extent ^---remove the extent at cpos 78723 ... unlock ip_alloc_sem inode unlock ocfs2_dio_end_io ocfs2_dio_end_io_write lock ip_alloc_sem ocfs2_mark_extent_written ocfs2_change_extent_flag ocfs2_search_extent_list ^---failed to find extent ... unlock ip_alloc_sem In most filesystems, fallocate is not compatible with racing with AIO+DIO, so fix it by adding to wait for all dio before fallocate/punch_hole like ext4.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.23 and later | 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.95, 6.6.35, 6.9.6, 6.10 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.23 and later Fixed in 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.95, 6.6.35, 6.9.6, 6.10 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 2.6.23 to before 4.19.317; 4.20 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.95; 6.2 to before 6.6.35; 6.7 to before 6.9.6 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.23 to before 4.19.317; 4.20 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.95; 6.2 to before 6.6.35; 6.7 to before 6.9.6 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.95, 6.6.35, 6.9.6, 6.10
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2024-40943
- 2026-10-03 Alias added: GHSA-rr6m-3x7m-qjff
References
Patch 8
- https://git.kernel.org/stable/c/3c26b5d21b1239e9c7fd31ba7d9b2d7bdbaa68d9
- https://git.kernel.org/stable/c/e8e2db1adac47970a6a9225f3858e9aa0e86287f
- https://git.kernel.org/stable/c/050ce8af6838c71e872e982b50d3f1bec21da40e
- https://git.kernel.org/stable/c/38825ff9da91d2854dcf6d9ac320a7e641e10f25
- https://git.kernel.org/stable/c/ea042dc2bea19d72e37c298bf65a9c341ef3fff3
- https://git.kernel.org/stable/c/3c361f313d696df72f9bccf058510e9ec737b9b1
- https://git.kernel.org/stable/c/117b9c009b72a6c2ebfd23484354dfee2d9570d2
- https://git.kernel.org/stable/c/952b023f06a24b2ad6ba67304c4c84d45bea2f18
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Sources
- CVE-2024-40943 · CVE Program
- CVE-2024-40943 · NVD
- FIRST EPSS
- GHSA-rr6m-3x7m-qjff · GitHub Advisory Database · CC BY 4.0
- CVE-2024-40943 · Red Hat security data · CC BY 4.0
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