From: Eric Anholt Date: Fri, 7 Dec 2018 19:16:53 +0000 (-0800) Subject: drm/sched: Always trace the dependencies we wait on, to fix a race. X-Git-Tag: v4.20.11~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=02edc9fd969fda27dad1c3f52aef68205428beb2;p=thirdparty%2Fkernel%2Fstable.git drm/sched: Always trace the dependencies we wait on, to fix a race. commit 82abf33766712d8446ea137a3400165e31bd12c7 upstream. The entity->dependency can go away completely once we've called drm_sched_entity_add_dependency_cb() (if the cb is called before we get around to tracing). The tracepoint is more useful if we trace every dependency instead of just ones that get callbacks installed, anyway, so just do that. Fixes any easy-to-produce OOPS when tracing the scheduler on V3D with "perf record -a -e gpu_scheduler:.\* glxgears" and DEBUG_SLAB enabled. Signed-off-by: Eric Anholt Reviewed-by: Christian König Cc: stable@vger.kernel.org Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index 3e22a54a99c25..2c02f5b03db8a 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -434,13 +434,10 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity) while ((entity->dependency = sched->ops->dependency(sched_job, entity))) { + trace_drm_sched_job_wait_dep(sched_job, entity->dependency); - if (drm_sched_entity_add_dependency_cb(entity)) { - - trace_drm_sched_job_wait_dep(sched_job, - entity->dependency); + if (drm_sched_entity_add_dependency_cb(entity)) return NULL; - } } /* skip jobs from entity that marked guilty */