CVE-2024-46778

What it actually does

The code incorrectly checks the address of a dml_bool_t pointer instead of dereferencing it to test the boolean value, causing always-true or always-false evaluation of UnboundedRequestEnabled and resulting in incorrect swath and DET configuration for AMD display hardware.

Why it matters to the business

Systems using affected AMD GPUs may experience display instability, crashes, or degraded graphics performance until the kernel is updated; high prevalence of the Linux kernel increases exposure across servers and workstations.

How an attack unfolds

An attacker with local access crafts display mode or connector configurations that reach the faulty check in the AMD display driver; the incorrect pointer test leads to invalid memory accesses or misconfigured hardware state that can be leveraged for denial of service or, in some cases, further kernel exploitation.

How to fix it

Update the Linux kernel to commit 4e2b49a85e7974d21364798c5d4aa8070aa864d9 or later stable releases containing the pointer-dereference fix; apply vendor backports if running distribution kernels.

How to confirm the fix worked

Verify the presence of the fix by checking kernel source or git log for the commit 4e2b49a85e7974d21364798c5d4aa8070aa864d9 in drivers/gpu/drm/amd/display; confirm no REVERSE_INULL warnings on the function after recompilation with static analysis.

Typical attack path

1. Obtain local user access on a Linux system with vulnerable AMD display driver
2. Trigger display reconfiguration via user-space graphics APIs or hotplug events
3. Reach CalculateSwathAndDETConfiguration with a non-null UnboundedRequestEnabled pointer
4. Exploit the always-true branch to induce invalid hardware state or memory corruption

How to detect it

Review kernel logs for oops or warnings originating from amd/display/dc/dml after display configuration changes; correlate with process activity that modifies DRM/KMS state.

What your security team should do

• Prioritize kernel updates on all AMD GPU hosts within standard change windows
• Monitor for display-related kernel oops or panics as indirect indicators
• Restrict unprivileged access to graphics APIs on high-value systems until patched