Executive brief
The Linux kernel's AMD GPU driver contains code that unnecessarily crashes the system when certain address alignment conditions are detected. By providing misaligned addresses to SDMA fence operations, a privileged user could trigger a kernel crash, causing system downtime. This is a hardening fix that converts critical failure assertions into warnings.
Technical details
The vulnerability is a denial of service flaw in the amdgpu SDMA v7.1 driver (drivers/gpu/drm/amd/amdgpu/sdma_v7_1.c). The code used BUG_ON() assertions to validate that fence addresses are 4-byte aligned, which unconditionally crashes the kernel if the condition is violated. The fix replaces BUG_ON() with WARN_ON(), allowing the driver to continue operation with a warning instead. Attack requires local access and GPU driver privileges (typically root or graphics group). An attacker can cause denial of service by invoking the vulnerable code path with misaligned addresses.
Affected products
- Linux Linux Kernel multiple versions prior to upstream patch c4f230b5
Timeline
- 2026-08-10: disclosed
- 2026-06-15: patched: upstream commit 767648c18d7872bbf54481ba846e055f7e1c0213