CVE-2024-40943

ocfs2: fix races between hole punching and AIO+DIO

MEDIUM

4.7

CVSS Score

Published: July 12, 2024 at 12:25 PM UTC

Updated: August 5, 2026 at 12:04 PM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

MEDIUM4.7

Exploit prediction

EPSS 0.2%

SSVC

No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

2.6.23 ≤ v < 4.19.3172.6.23 ≤ v < 5.10.2212.6.23 ≤ v < 5.15.1622.6.23 ≤ v < 5.4.2792.6.23 ≤ v < 6.1.952.6.23 ≤ v < 6.102.6.23 ≤ v < 6.6.352.6.23 ≤ v < 6.9.64.20 ≤ v < 5.4.2795.11 ≤ v < 5.15.1625.16 ≤ v < 6.1.955.5 ≤ v < 5.10.2216.2 ≤ v < 6.6.356.7 ≤ v < 6.9.62.6.23b25801038da5823bba1b5440a57ca68afc51b6bd

Vendor states this is fixed in 050ce8af6838c71e872e982b50d3f1bec21da40e (fixed)

Vendor states this is fixed in 117b9c009b72a6c2ebfd23484354dfee2d9570d2 (fixed)

Vendor states this is fixed in 38825ff9da91d2854dcf6d9ac320a7e641e10f25 (fixed)

Vendor states this is fixed in 3c26b5d21b1239e9c7fd31ba7d9b2d7bdbaa68d9 (fixed)

Vendor states this is fixed in 3c361f313d696df72f9bccf058510e9ec737b9b1 (fixed)

Vendor states this is fixed in 952b023f06a24b2ad6ba67304c4c84d45bea2f18 (fixed)

Vendor states this is fixed in e8e2db1adac47970a6a9225f3858e9aa0e86287f (fixed)

Vendor states this is fixed in ea042dc2bea19d72e37c298bf65a9c341ef3fff3 (fixed)

Vendor states this is fixed in 2.6.23 (unaffected)

Vendor states this is fixed in 4.19.317 (unaffected)

Vendor states this is fixed in 5.10.221 (unaffected)

Vendor states this is fixed in 5.15.162 (unaffected)