Affected: Linux

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

drm/xe/guc: Hold device ref until queue teardown completes

GuC exec queue destruction can run asynchronously. If the final device put happens from a destroy worker, drmm cleanup can end up draining the same workqueue and deadlock.

Hold a drm_device reference for the queue lifetime and drop it after queue teardown completes. This keeps drmm cleanup from running while async destroy work is still pending.

Move GuC destroy work to a module-lifetime Xe workqueue and flush it on PCI remove so hot-unbind/rebind still waits for pending destroy work.

With queue-held device refs, guc_submit_sw_fini() cannot run with live GuC IDs. Replace the fini wait with an assertion and remove the unused fini_wq.

v2: - Rebase

v3: - Switch to queue-lifetime drm_dev_get()/drm_dev_put() model. (Matt) - Queue async teardown on system_dfl_wq instead of xe->destroy_wq. (Matt) - Drop separate deferred drm_dev_put worker. - Remove stale drain_workqueue(xe->destroy_wq) from guc_submit_sw_fini().

v4: - Replace the guc_submit_sw_fini() wait with an assertion and remove the now-unused fini_wq. (sashiko)

v5: - Move destroy work to a module-lifetime Xe workqueue instead of system_dfl_wq. (Matt) - Flush the module-lifetime destroy workqueue during PCI remove to preserve the old device-remove wait semantics.

v6: - Keep SVM pagemap destroy work on the per-device destroy_wq to avoid letting it outlive the…