CVE-2024-40951: ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-12 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger() bdev->bd_super has been removed and commit 8887b94d9322 change the usage from bdev->bd_super to b_assoc_map->host->i_sb. Since ocfs2 hasn't set bh->b_assoc_map, it will trigger NULL pointer dereference when calling into ocfs2_abort_trigger(). Actually this was pointed out in history, see commit 74e364ad1b13. But I've made a mistake when reviewing commit 8887b94d9322 and then re-introduce this regression. Since we cannot revive bdev in buffer head, so fix this issue by initializing all types of ocfs2 triggers when fill super, and then get the specific ocfs2 trigger from ocfs2_caching_info when access journal. [joseph.qi@linux.alibaba.com: v2]

Affected products

Linux kernel: from 6.6 before 6.6.36; from 6.7 before 6.9.7; 6.10-rc1, 6.10-rc2, 6.10-rc3, 6.10-rc4 — fixed in 6.6.36, 6.9.7

How to fix

Upgrade to a fixed version: Linux kernel 6.6.36, 6.9.7. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-40951 or the next vulnerability affects your stack