Am 16.07.2018 um 11:01 schrieb Zhang, Jerry (Junwei):
> On 07/16/2018 04:31 PM, Christian König wrote:
>> Am 16.07.2018 um 04:59 schrieb Junwei Zhang:
>>> To check rq pointer before adding entity into it.
>>> That avoids NULL pointer access in some case.
>>>
>>> Suggested-by: Christian König <christian.koenig at amd.com>
>>> Signed-off-by: Junwei Zhang <Jerry.Zhang at amd.com>
>>> ---
>>> Â drivers/gpu/drm/scheduler/gpu_scheduler.c | 4 ++++
>>> Â 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c
>>> b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>>> index 16bf446..5e5268d 100644
>>> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
>>> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
>>> @@ -91,6 +91,10 @@ static void drm_sched_rq_add_entity(struct
>>> drm_sched_rq *rq,
>>> Â {
>>> Â Â Â Â Â if (!list_empty(&entity->list))
>>> Â Â Â Â Â Â Â Â Â return;
>>> +Â Â Â if (!rq) {
>>> +Â Â Â Â Â Â Â DRM_ERROR("rq is NULL!\n");
>>> +Â Â Â Â Â Â Â return;
>>> +Â Â Â }
>>
>> Better put that into drm_sched_entity_push_job(), e.g. something like:
>
> Considered that as well.
> Just be afraid of someone else could call it in another place without
> rq checking in the future.
Well that's exactly the reason why I wanted to have the check in
drm_sched_rq_add_entity().
Calling drm_sched_rq_add_entity() will a NULL rq is illegal and that
should be avoided in the caller instead of more or less silently dropped
in the function.
Regards,
Christian.
>
> Regards,
> Jerry
>
>>
>> /* first job wakes up scheduler */
>> if (first) {
>> Â Â Â Â /* Add the entity to the run queue */
>> Â Â Â Â spin_lock(&entity->rq_lock);
>> Â Â Â Â if (!entity->rq) {
>> Â Â Â Â Â Â Â Â DRM_ERROR("Trying to push to killed entity!\n");
>> ....
>>
>> Regards,
>> Christian.
>>
>>> Â Â Â Â Â spin_lock(&rq->lock);
>>> Â Â Â Â Â list_add_tail(&entity->list, &rq->entities);
>>> Â Â Â Â Â spin_unlock(&rq->lock);
>>
