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

drm/xe/pt: Fix NULL pointer dereference in xe_pt_zap_ptes_entry()

The page-table walk framework may pass a NULL *child pointer for
unpopulated entries. xe_pt_zap_ptes_entry() called container_of(*child)
before checking for NULL, then dereferenced the result, causing a crash.

Move the container_of() call after a NULL guard, so the function returns
early instead of proceeding with an invalid pointer. XE_WARN_ON is kept
to help root cause the issue, but we now bail instead of crashing the
driver.

v2: Comment that triggering XE_WARN_ON is unexpected behavior (Matt Brost)

(cherry picked from commit b9297d19d9df5d4b6c994648570c5dcd1cac68ff)