In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: force complete the MES ring fences on reset The MES scheduler ring has no drm scheduler (no_scheduler = true), so it is skipped by the force-completion loo…

Overview

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: force complete the MES ring fences on reset

The MES scheduler ring has no drm scheduler (no_scheduler = true), so it is skipped by the force-completion loop in amdgpu_device_pre_asic_reset(). It uses a polling fence whose hw value lives in wb (GTT) memory and survives a MODE1 reset, while fence_drv.sync_seq keeps advancing for every packet.

When the reset is triggered because MES itself stopped responding, the timed-out packets advance sync_seq past the last hw fence value MES wrote. After resume the first MES submission polls forever on a seq that is never written back, failing the resume and wedging the box on a second reset:

amdgpu: MES ring buffer is full. amdgpu: ERROR ring gfx_0.0.0 test failed (-110) amdgpu: resume of IP block <gfx_v11_0> failed -110 amdgpu: GPU reset end with ret = -110

Force complete the MES scheduler ring fences together with the scheduler rings so their hw fence is realigned to sync_seq.

v2: cover all XCCs (one scheduler ring each), not just mes.ring[0].

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.