Commit 439be5c5 authored by Philipp Stanner's avatar Philipp Stanner
Browse files

drm/todo: Add entry for unlocked drm/sched rq readers 



Runqueues are currently almost everywhere being read unlocked in
drm/sched. At XDC 2025, the assembled developers were unsure whether
that's legal and whether it can be fixed. Someone should find out.

Add a todo entry for the unlocked runqueue reader problem.

Acked-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarPhilipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20251107135701.244659-4-phasta@kernel.org
parent 9d56cbaf

Documentation/gpu/todo.rst

+14 −0
Original line number Diff line number Diff line
@@ -909,6 +909,20 @@ Contact: Christian König <christian.koenig@amd.com> 


Level: Advanced



Add locking for runqueues

-------------------------



There is an old FIXME by Sima in include/drm/gpu_scheduler.h. It details that

struct drm_sched_rq is read at many places without any locks, not even with a

READ_ONCE. At XDC 2025 no one could really tell why that is the case, whether

locks are needed and whether they could be added. (But for real, that should

probably be locked!). Check whether it's possible to add locks everywhere, and

do so if yes.



Contact: Philipp Stanner <phasta@kernel.org>



Level: Intermediate



Outside DRM

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