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

> A null pointer dereference in the Linux kernel's HMM test module can cause a system crash when memory allocation fails during device eviction.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jun 2024
- **Updated:** 11 May 2026
- **Also known as:** AZL-48310, BELL-CVE-2024-38543, DEBIAN-CVE-2024-38543, GHSA-3q6x-gxwh-88p9, ROOT-OS-DEBIAN-11-CVE-2024-38543, ROOT-OS-UBUNTU-2204-CVE-2024-38543, UBUNTU-CVE-2024-38543

## What is CVE-2024-38543?

CVE-2024-38543 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2024-38543?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-38543?

Apply the vendor's patch.

## Is CVE-2024-38543 being exploited?

There is no known exploitation of CVE-2024-38543 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-38543 and fix it if it is affected.

What it is: CVE-2024-38543 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-38543 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-38543/ (Markdown: https://insights.sbomify.com/CVE-2024-38543/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-38543
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-38543
- OSV: https://osv.dev/vulnerability/CVE-2024-38543

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-38543/
Summaries are generated and may contain mistakes; the official description above is the record.