CVE-2025-40340

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

drm/xe: Fix oops in xe_gem_fault when running core_hotunplug test.

I saw an oops in xe_gem_fault when running the xe-fast-feedback

testlist against the realtime kernel without debug options enabled.

The panic happens after core_hotunplug unbind-rebind finishes.

Presumably what happens is that a process mmaps, unlocks because

of the FAULT_FLAG_RETRY_NOWAIT logic, has no process memory left,

causing ttm_bo_vm_dummy_page() to return VM_FAULT_NOPAGE, since

there was nothing left to populate, and then oopses in

"mem_type_is_vram(tbo->resource->mem_type)" because tbo->resource

is NULL.

It's convoluted, but fits the data and explains the oops after

the test exits.