Tvrkos patches added RCU protection to the returned strings from get_timeline_name()/get_driver_name() callbacks of the dma_fence backends.
This fixed use after free problems for a couple of drivers, but we never documented the consequences for the drm_sched_fence. Add a few words on the function documentation to note that we need an RCU grace period between signaling the last scheduler fence and scheduler teardown. Signed-off-by: Christian König <[email protected]> --- drivers/gpu/drm/scheduler/sched_main.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c index 6cb6f95464938..f73c5141b4e5c 100644 --- a/drivers/gpu/drm/scheduler/sched_main.c +++ b/drivers/gpu/drm/scheduler/sched_main.c @@ -1203,6 +1203,11 @@ static void drm_sched_cancel_remaining_jobs(struct drm_gpu_scheduler *sched) * is implemented, all jobs will be canceled through it and afterwards cleaned * up through &struct drm_sched_backend_ops.free_job. If cancel_job is not * implemented, memory could leak. + * + * The user must wait one RCU grace period between signaling the last hardware- + * fence and calling this function because the timeline name returned by + * scheduler fences must stay valid until all readers have exited their RCU read + * side critical section. */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { -- 2.43.0
