Patch "drm/sched: Add locking to drm_sched_entity_modify_sched" has been added to the 5.15-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/sched: Add locking to drm_sched_entity_modify_sched

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-sched-add-locking-to-drm_sched_entity_modify_sched.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From 4286cc2c953983d44d248c9de1c81d3a9643345c Mon Sep 17 00:00:00 2001
From: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Date: Fri, 13 Sep 2024 17:05:52 +0100
Subject: drm/sched: Add locking to drm_sched_entity_modify_sched
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>

commit 4286cc2c953983d44d248c9de1c81d3a9643345c upstream.

Without the locking amdgpu currently can race between
amdgpu_ctx_set_entity_priority() (via drm_sched_entity_modify_sched()) and
drm_sched_job_arm(), leading to the latter accesing potentially
inconsitent entity->sched_list and entity->num_sched_list pair.

v2:
 * Improve commit message. (Philipp)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Fixes: b37aced31eb0 ("drm/scheduler: implement a function to modify sched list")
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Luben Tuikov <ltuikov89@gmail.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Cc: Philipp Stanner <pstanner@redhat.com>
Cc: <stable@vger.kernel.org> # v5.7+
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240913160559.49054-2-tursulin@igalia.com
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/scheduler/sched_entity.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -99,8 +99,10 @@ void drm_sched_entity_modify_sched(struc
 {
 	WARN_ON(!num_sched_list || !sched_list);
 
+	spin_lock(&entity->rq_lock);
 	entity->sched_list = sched_list;
 	entity->num_sched_list = num_sched_list;
+	spin_unlock(&entity->rq_lock);
 }
 EXPORT_SYMBOL(drm_sched_entity_modify_sched);
 


Patches currently in stable-queue which might be from tvrtko.ursulin@igalia.com are

queue-5.15/drm-sched-add-locking-to-drm_sched_entity_modify_sched.patch