UBUNTU-CVE-2026-98391: Medium severity ubuntu/linux-hwe-edge vulnerability

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Guard page-fault worker with runtime PM check During VM teardown, the VM's runtime PM reference is dropped asynchronously, allowing the device to autosuspend while stale page faults belonging to the now-dead VM are still queued. When the page-fault worker later tries to ack one of these, it calls into gucctsendlocked() on an already-suspended device, tripping:   Assertion !xepmruntimesuspended(xe) failed!   WARNING at xedevice.c:1267 xedeviceassertmemaccess+0x11c/0x140 [xe] A live VM/exec queue always holds a PM reference while it has outstanding work, so if the device is suspended at ack time, the owning context is already gone and the fault is stale. Take a runtime PM reference across the entire pagefault queue worker to safely deliver acks for torn-down VMs. v3: - Move PM ref to the generic xepagefaultqueuework using guard(xepmruntime)(xe) instead of tracking it in the GuC backend(Matt Brost). v2: - Hold PM ref across the entire batch (begin/end) instead of per-ack. This prevents the device from autosuspending mid-batch, which would leave writeonly acks written but the end flush skipped, and skip counter++, desyncing the cadence check.(Himal) - Add a comment explaining stale faults.(Himal) (cherry picked from commit fcc2431d2213dc4d04250c4f1ae87d9c3ae0d455) [Rodrigo: Added xedevice struct for compatibility while cherry-picking]