CVE-2024-53131: nilfs2: fix null-ptr-deref in block_touch_buffer tracepoint

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: 2024-12-04 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix null-ptr-deref in block_touch_buffer tracepoint Patch series "nilfs2: fix null-ptr-deref bugs on block tracepoints". This series fixes null pointer dereference bugs that occur when using nilfs2 and two block-related tracepoints. This patch (of 2): It has been reported that when using "block:block_touch_buffer" tracepoint, touch_buffer() called from __nilfs_get_folio_block() causes a NULL pointer dereference, or a general protection fault when KASAN is enabled. This happens because since the tracepoint was added in touch_buffer(), it references the dev_t member bh->b_bdev->bd_dev regardless of whether the buffer head has a pointer to a block_device structure. In the current implementation, the block_device structure is set after the function returns to the caller. Here, touch_buffer() is used to mark the folio/page that owns the buffer head as accessed, but the common search helper for folio/page used by the caller function was optimized to mark the folio/page as accessed when it was reimplemented a long time ago, eliminating the need to call touch_buffer() here in the first place. So this solves the issue by eliminating the touch_buffer() call itself.

Affected products

Linux kernel: from 3.9 before 6.1.119; from 6.6.0 before 6.6.63; from 6.11.0 before 6.11.10 — fixed in 6.1.119, 6.11.10, 6.6.63

How to fix

Upgrade to a fixed version: Linux kernel 6.1.119, 6.11.10, 6.6.63. Check the vendor advisory for mitigations.

References

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