CVE-2024-56752

What it actually does

Missing unlock of gr->fecs.mutex on error return from gf100_grctx_generate() inside gf100_gr_chan_new() leaves the mutex held, causing inconsistent locking state in the Nouveau GF100 graphics engine.

Why it matters to the business

Graphics driver operations may hang or deadlock on systems using the affected Nouveau driver, disrupting display, compute, or GPU-accelerated workloads until reboot.

How an attack unfolds

An attacker with local access crafts conditions that cause gf100_grctx_generate() to fail inside gf100_gr_chan_new(); the missing unlock leaves the mutex acquired, so any later attempt to acquire it blocks indefinitely, producing a denial-of-service via driver deadlock.

How to fix it

Apply the upstream kernel fix that adds the missing unlock before returning the error; for packaged distributions update to the corrected kernel or driver package containing the resolution for CVE-2024-56752.

How to confirm the fix worked

Confirm the patch is present by inspecting drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c around line 480 for the unlock call on the error path; recompile and test channel creation under failure injection to verify consistent mutex state.

Typical attack path

1. Obtain local unprivileged access on a system using the Nouveau driver
2. Trigger channel creation that reaches the error path in gf100_gr_chan_new()
3. Leave gr->fecs.mutex held after function return
4. Induce subsequent driver code paths that attempt to acquire the same mutex

How to detect it

Review kernel logs for Nouveau channel creation failures around gf100_gr_chan_new and subsequent mutex-related stalls; correlate with dmesg entries showing inconsistent lock state or hung task warnings involving gr->fecs.mutex.

What your security team should do

• Prioritize kernel or Nouveau driver updates on all systems exposing the affected code path
• Monitor for graphics-related hangs coinciding with channel allocation failures
• Restrict unprivileged local access where feasible until patches are deployed