Wind River Support Network

Description

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 guc_ct_send_locked() on an already-suspended device, tripping:    Assertion `!xe_pm_runtime_suspended(xe)` failed!   WARNING at xe_device.c:1267 xe_device_assert_mem_access+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 xe_pagefault_queue_work using    guard(xe_pm_runtime)(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 write_only 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 xe_device struct for compatibility while cherry-picking]
Data source: kernel.org (416baaa9-dc9f-4396-8d5f-8c081fb06d67)