On 10/29/25 10:11, Pierre-Eric Pelloux-Prayer wrote:
https://gitlab.freedesktop.org/mesa/mesa/-/issues/13908 pointed out a possible deadlock:
[ 1231.611031] Possible interrupt unsafe locking scenario:
[ 1231.611033] CPU0 CPU1 [ 1231.611034] ---- ---- [ 1231.611035] lock(&xa->xa_lock#17); [ 1231.611038] local_irq_disable(); [ 1231.611039] lock(&fence->lock); [ 1231.611041] lock(&xa->xa_lock#17); [ 1231.611044] <Interrupt> [ 1231.611045] lock(&fence->lock); [ 1231.611047] *** DEADLOCK ***
My initial fix was to replace xa_erase by xa_erase_irq, but Christian pointed out that calling dma_fence_add_callback from a callback can also deadlock if the signalling fence and the one passed to dma_fence_add_callback share the same lock.
To fix both issues, the code iterating on dependencies and re-arming them is moved out to drm_sched_entity_kill_jobs_work.
Suggested-by: Christian König christian.koenig@amd.com Signed-off-by: Pierre-Eric Pelloux-Prayer pierre-eric.pelloux-prayer@amd.com
Reviewed-by: Christian König christian.koenig@amd.com
drivers/gpu/drm/scheduler/sched_entity.c | 34 +++++++++++++----------- 1 file changed, 19 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index c8e949f4a568..fe174a4857be 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -173,26 +173,15 @@ int drm_sched_entity_error(struct drm_sched_entity *entity) } EXPORT_SYMBOL(drm_sched_entity_error); +static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
struct dma_fence_cb *cb);static void drm_sched_entity_kill_jobs_work(struct work_struct *wrk) { struct drm_sched_job *job = container_of(wrk, typeof(*job), work);
- drm_sched_fence_scheduled(job->s_fence, NULL);
- drm_sched_fence_finished(job->s_fence, -ESRCH);
- WARN_ON(job->s_fence->parent);
- job->sched->ops->free_job(job);
-}
-/* Signal the scheduler finished fence when the entity in question is killed. */ -static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
struct dma_fence_cb *cb)-{
- struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
finish_cb);
- struct dma_fence *f; unsigned long index;
- dma_fence_put(f);
- /* Wait for all dependencies to avoid data corruptions */ xa_for_each(&job->dependencies, index, f) { struct drm_sched_fence *s_fence = to_drm_sched_fence(f);
@@ -220,6 +209,21 @@ static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f, dma_fence_put(f); }
- drm_sched_fence_scheduled(job->s_fence, NULL);
- drm_sched_fence_finished(job->s_fence, -ESRCH);
- WARN_ON(job->s_fence->parent);
- job->sched->ops->free_job(job);
+}
+/* Signal the scheduler finished fence when the entity in question is killed. */ +static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
struct dma_fence_cb *cb)+{
- struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
finish_cb);- dma_fence_put(f);
- INIT_WORK(&job->work, drm_sched_entity_kill_jobs_work); schedule_work(&job->work);
}