# CVE-2025-40329: drm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb

> A race condition in the Linux kernel's DRM scheduler can cause a deadlock, leading to a local denial of service.

- **Severity:** Not scored
- **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:** 9 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-40329, DEBIAN-CVE-2025-40329, GHSA-g9x6-c54r-8jg6, ROOT-OS-DEBIAN-13-CVE-2025-40329, ROOT-OS-UBUNTU-2404-CVE-2025-40329, UBUNTU-CVE-2025-40329

## What is CVE-2025-40329?

CVE-2025-40329 is a vulnerability in Linux, published on 9 Dec 2025. 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:

drm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb

The Mesa issue referenced below pointed out a possible deadlock:

[ 1231.611031]  Possible interrupt unsafe locking scenario:

[ 1231.611033]        CPU0                    CPU1
[ 1231.611034]        ----                    ----
[ 1231.611035]   lock(&xa->xa_lock#17);
[ 1231.611038]                                local_irq_disable();
[ 1231.611039]                                lock(&fence->lock);
[ 1231.611041]                                lock(&xa->xa_lock#17);
[ 1231.611044]   <Interrupt>
[ 1231.611045]     lock(&fence->lock);
[ 1231.611047]
                *** DEADLOCK ***

In this example, CPU0 would be any function accessing job->dependencies
through the xa_* functions that don't disable interrupts (eg:
drm_sched_job_add_dependency(), drm_sched_entity_kill_jobs_cb()).

CPU1 is executing drm_sched_entity_kill_jobs_cb() as a fence signalling
callback so in an interrupt context. It will deadlock when trying to
grab the xa_lock which is already held by CPU0.

Replacing all xa_* usage by their xa_*_irq counterparts would fix
this issue, but Christian pointed out another issue: dma_fence_signal
takes fence.lock and so does dma_fence_add_callback.

  dma_fence_signal() // locks f1.lock
  -> drm_sched_entity_kill_jobs_cb()
  -> foreach dependencies
     -> dma_fence_add_callback() // locks f2.lock

This will deadlock if f1 and f2 share the same spinlock.

To fix both issues, the code iterating on dependencies and re-arming them
is moved out to drm_sched_entity_kill_jobs_work().

[phasta: commit message nits]

## Which versions are affected by CVE-2025-40329?


## How do I fix CVE-2025-40329?

Apply the vendor's patch.

## Is CVE-2025-40329 being exploited?

There is no known exploitation of CVE-2025-40329 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40329 and fix it if it is affected.

What it is: CVE-2025-40329 is a vulnerability in Linux, published on 9 Dec 2025. 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-2025-40329 in the wild and no public exploit code.

Affected product: Linux. 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-2025-40329/ (Markdown: https://insights.sbomify.com/CVE-2025-40329/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40329
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40329
- OSV: https://osv.dev/vulnerability/CVE-2025-40329

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40329/
Summaries are generated and may contain mistakes; the official description above is the record.