Affected: Linux

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.probe_display. It gets set to false if there's no display after intel_display_device_probe(). However, the display may also be disabled via fuses, detected at a later time in intel_display_device_info_runtime_init().

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

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

Move intel_display_device_info_runtime_init() 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 for_each_intel_crtc() 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 wo…