FAILED: patch "[PATCH] drm/sched: Fix race in drm_sched_entity_select_rq()" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] drm/sched: Fix race in drm_sched_entity_select_rq()" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x d25e3a610bae03bffc5c14b5d944a5d0cd844678
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025110342-pristine-visibly-505b@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d25e3a610bae03bffc5c14b5d944a5d0cd844678 Mon Sep 17 00:00:00 2001
From: Philipp Stanner <phasta@kernel.org>
Date: Wed, 22 Oct 2025 08:34:03 +0200
Subject: [PATCH] drm/sched: Fix race in drm_sched_entity_select_rq()

In a past bug fix it was forgotten that entity access must be protected
by the entity lock. That's a data race and potentially UB.

Move the spin_unlock() to the appropriate position.

Cc: stable@vger.kernel.org # v5.13+
Fixes: ac4eb83ab255 ("drm/sched: select new rq even if there is only one v3")
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Philipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20251022063402.87318-2-phasta@kernel.org

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 5a4697f636f2..aa222166de58 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -552,10 +552,11 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 		drm_sched_rq_remove_entity(entity->rq, entity);
 		entity->rq = rq;
 	}
-	spin_unlock(&entity->lock);
 
 	if (entity->num_sched_list == 1)
 		entity->sched_list = NULL;
+
+	spin_unlock(&entity->lock);
 }
 
 /**

[PATCH 6.6.y] drm/sched: Fix race in drm_sched_entity_select_rq()

[Sasha Levin]

From: Philipp Stanner <phasta@kernel.org>

[ Upstream commit d25e3a610bae03bffc5c14b5d944a5d0cd844678 ]

In a past bug fix it was forgotten that entity access must be protected
by the entity lock. That's a data race and potentially UB.

Move the spin_unlock() to the appropriate position.

Cc: stable@vger.kernel.org # v5.13+
Fixes: ac4eb83ab255 ("drm/sched: select new rq even if there is only one v3")
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Signed-off-by: Philipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20251022063402.87318-2-phasta@kernel.org
[ adapted lock field name from entity->lock to entity->rq_lock ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/scheduler/sched_entity.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 245a1ef5278e8..a13d6186af852 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -531,10 +531,11 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 		drm_sched_rq_remove_entity(entity->rq, entity);
 		entity->rq = rq;
 	}
-	spin_unlock(&entity->rq_lock);
 
 	if (entity->num_sched_list == 1)
 		entity->sched_list = NULL;
+
+	spin_unlock(&entity->rq_lock);
 }
 
 /**
-- 
2.51.0