CVE-2022-48766

What it actually does

Missing FPU context wrapping around dcn301_calculate_wm_and_dlg allows floating-point operations to execute in non-FPU kernel context, producing warnings and kernel panics on AMD DCN 3.01 hardware.

Why it matters to the business

Systems using affected Linux kernels with AMD display hardware may experience unexpected crashes, leading to downtime and potential data loss during graphics initialization or mode changes; the high number of downstream kernel dependents increases patch urgency.

How an attack unfolds

An attacker triggers the vulnerable display watermark and deadline calculation path on DCN 3.01 hardware; without FPU wrapping the kernel panics. The listed threat actor context does not apply to this DoS-class issue.

How to fix it

Update to a kernel containing commit 456ba2433844a6483cc4c933aa8f43d24575e341 or later; rebuild and reboot all affected systems.

How to confirm the fix worked

Confirm the commit 456ba2433844a6483cc4c933aa8f43d24575e341 is present in the running kernel source or binary; attempt display mode changes that previously triggered the WARN/panic path.

Typical attack path

1. Obtain local access or trigger graphics mode change on affected AMD hardware
2. Cause dcn301_calculate_wm_and_dlg to be invoked without FPU context
3. Kernel emits warnings and panics

How to detect it

Review kernel logs for FPU-related warnings or panics originating from amd/display during display initialization; correlate with AMD GPU hardware presence.

What your security team should do

• Prioritize kernel upgrades to the fixed commit on all AMD DCN 3.01 systems within the next maintenance window
• Monitor vendor kernel updates and backports for stable branches
• Test graphics workloads after patching to verify absence of panics