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

drm/xe/display: fix oops in suspend/shutdown without display

The xe driver keeps track of whether to probe display, and whether display hardware is there, using xe->info.probedisplay. It gets set to false if there's no display after inteldisplaydeviceprobe(). However, the display may also be disabled via fuses, detected at a later time in inteldisplaydeviceinforuntimeinit().

In this case, the xe driver does foreachintelcrtc() on uninitialized mode config in xedisplayflushcleanupwork(), leading to a NULL pointer dereference, and generally calls display code with display info cleared.

Check for inteldisplaydevicepresent() after inteldisplaydeviceinforuntimeinit(), and reset xe->info.probedisplay as necessary. Also do unsetdisplayfeatures() for completeness, although display runtime init has already done that. This will need to be unified across all cases later.

Move inteldisplaydeviceinforuntimeinit() call slightly earlier, similar to i915, to avoid a bunch of unnecessary setup for no display cases.

Note #1: The xe driver has no business doing low level display plumbing like foreachintelcrtc() to begin with. It all needs to happen in display code.

Note #2: The actual bug is present already in commit 44e694958b95 ("drm/xe/display: Implement display support"), but the oops was likely introduced later at commit ddf6492e0e50 ("drm/xe/display: Make display suspend/resume work on discrete").

(cherry picked from commit 7c3eb9f47533220888a67266448185fd0775d4da)