CVE-2023-52825

What it actually does

Race condition between asynchronous MMU and migration callbacks allows concurrent unref of svm_bo leading to use-after-free of vram buffer.

Why it matters to the business

Systems running affected Linux kernels with AMD GPU SVM support face risk of kernel instability, crashes, or local privilege escalation; widespread Linux distributions increase exposure across servers and workstations.

How an attack unfolds

An attacker with local access triggers concurrent SVM operations that invoke the MMU callback and migrate-to-ram callback simultaneously, racing the unref of svm_bo and dereferencing freed memory to achieve use-after-free.

How to fix it

Update the Linux kernel to the commit 7d43cdd22cd81a2b079e864c4321b9aba4c6af34 or later stable releases containing the synchronized svm_bo unref fix.

How to confirm the fix worked

Verify the running kernel git commit or package version includes 7d43cdd22cd81a2b079e864c4321b9aba4c6af34; attempt to reproduce the race under load and confirm absence of use-after-free reports in kernel logs.

Typical attack path

1. Obtain local code execution on target Linux system with AMD GPU and SVM enabled
2. Craft workload that allocates SVM ranges and forces concurrent migration and MMU invalidation
3. Trigger the two async unref paths without synchronization
4. Reuse freed svm_bo pointer to corrupt kernel memory or redirect execution

How to detect it

Review kernel logs for use-after-free or general protection faults referencing svm_bo or amdkfd; correlate with processes performing heavy SVM or GPU memory migration activity.

What your security team should do

• Prioritize kernel updates on all AMD GPU systems within patch windows
• Restrict unprivileged local access where feasible until patched
• Monitor kernel oops and use-after-free reports in SVM code paths