Merge tag 'drm-misc-fixes-2024-03-28' of https://gitlab.freedesktop.org/drm/misc/kernel into drm-fixes

Short summary of fixes pull:

bridge:
- select DRM_KMS_HELPER

dma-buf:
- fix NULL-pointer deref

dp:
- fix div-by-zero in DP MST unplug code

fbdev:
- select FB_IOMEM_FOPS for SBus

nouveau:
- dmem: handle kcalloc() allocation failures

qxl:
- remove unused variables

rockchip:
- vop2: remove support for AR30 and AB30 formats

sched:
- fix NULL-pointer deref

vmwgfx:
- debugfs: create ttm_resource_manager entry only if needed

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240328134417.GA8673@localhost.localdomain

1 files changed, 9 insertions, 3 deletions

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 3c4f5a392b06..58c8161289fe 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -71,13 +71,19 @@ int drm_sched_entity_init(struct drm_sched_entity *entity,
 	entity->guilty = guilty;
 	entity->num_sched_list = num_sched_list;
 	entity->priority = priority;
+	/*
+	 * It's perfectly valid to initialize an entity without having a valid
+	 * scheduler attached. It's just not valid to use the scheduler before it
+	 * is initialized itself.
+	 */
 	entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
 	RCU_INIT_POINTER(entity->last_scheduled, NULL);
 	RB_CLEAR_NODE(&entity->rb_tree_node);
 
-	if (!sched_list[0]->sched_rq) {
-		/* Warn drivers not to do this and to fix their DRM
-		 * calling order.
+	if (num_sched_list && !sched_list[0]->sched_rq) {
+		/* Since every entry covered by num_sched_list
+		 * should be non-NULL and therefore we warn drivers
+		 * not to do this and to fix their DRM calling order.
 		 */
 		pr_warn("%s: called with uninitialized scheduler\n", __func__);
 	} else if (num_sched_list) {