Linux kernel (drivers/gpu/drm/xe): The observation/OA path reuses one batch buffer and appends a batch-end command on

Impact

The observation/OA path reuses one batch buffer and appends a batch-end command on every reconfiguration, so repeated use runs the write past the end of the allocation. The kernel overwrites adjacent memory and the GPU then executes whatever follows the batch - kernel heap corruption driven entirely from userspace, plus GPU-side execution of unintended commands.

Who can reach it

Tenant holding /dev/dri/renderD* on Intel xe opens an observation (OA) stream against its own exec queue and repeatedly reconfigures the same metric set. Per-queue OA does not require CAP_PERFMON, so this is reachable from an ordinary tenant container.

What to do

Update to a kernel carrying the fix (stable commits below; no fixed_in published). Interim: set perf_stream_paranoid to block observation streams, or deny the xe observation ioctl to tenant workloads.

References