CVE-2024-38543: lib/test_hmm.c: handle src_pfns and dst_pfns allocation failure

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: 2024-06-19 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: lib/test_hmm.c: handle src_pfns and dst_pfns allocation failure The kcalloc() in dmirror_device_evict_chunk() will return null if the physical memory has run out. As a result, if src_pfns or dst_pfns is dereferenced, the null pointer dereference bug will happen. Moreover, the device is going away. If the kcalloc() fails, the pages mapping a chunk could not be evicted. So add a __GFP_NOFAIL flag in kcalloc(). Finally, as there is no need to have physically contiguous memory, Switch kcalloc() to kvcalloc() in order to avoid failing allocations.

Affected products

Linux kernel: from 5.8 before 6.1.93; from 6.2 before 6.6.33; from 6.7 before 6.8.12; from 6.9 before 6.9.3 — fixed in 6.1.93, 6.6.33, 6.8.12, 6.9.3

How to fix

Upgrade to a fixed version: Linux kernel 6.1.93, 6.6.33, 6.8.12, 6.9.3. Check the vendor advisory for mitigations.

References

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