CVE-2023-53552 — Use After Free in Linux

In the Linux kernel, the following vulnerability has been resolved: drm/i915: mark requests for GuC virtual engines to avoid use-after-free References to i915_requests may be trapped by userspace inside a sync_file or dmabuf (dma-resv) and held indefinitely across different proceses. To counter-act the memory leaks, we try to not to keep references from the request past their completion. On the other side on fence release we need to know if rq->engine is valid and points to hw engine (true for…