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

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[ Upstream commit 1cda3c755b ]

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.

Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://lore.kernel.org/r/20250715152057.23254-2-dev@lankhorst.se
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Maarten Lankhorst 2025-07-15 17:20:58 +02:00 • committed by Greg Kroah-Hartman

parent efffbbbe80

commit 99428bd612

1 changed files with 16 additions and 12 deletions

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drivers/gpu/drm/xe/xe_bo.c

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