Sorry, please take your time.
Best wishes
Emily Deng
>-----Original Message-----
>From: Koenig, Christian <Christian.Koenig@xxxxxxx>
>Sent: Friday, November 8, 2019 5:08 PM
>To: Deng, Emily <Emily.Deng@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>Subject: Re: [PATCH] drm/amdgpu: Fix the null pointer issue for tdr
>
>Am 08.11.19 um 09:52 schrieb Deng, Emily:
>> Ping.....
>
>You need to give me at least enough time to wake up :)
>
>>
>>
>> Best wishes
>> Emily Deng
>>
>>
>>
>>> -----Original Message-----
>>> From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of
>>> Deng, Emily
>>> Sent: Friday, November 8, 2019 10:56 AM
>>> To: Koenig, Christian <Christian.Koenig@xxxxxxx>; amd-
>>> gfx@xxxxxxxxxxxxxxxxxxxxx
>>> Subject: RE: [PATCH] drm/amdgpu: Fix the null pointer issue for tdr
>>>
>>>> -----Original Message-----
>>>> From: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
>>>> Sent: Thursday, November 7, 2019 7:28 PM
>>>> To: Deng, Emily <Emily.Deng@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>>>> Subject: Re: [PATCH] drm/amdgpu: Fix the null pointer issue for tdr
>>>>
>>>> Am 07.11.19 um 11:25 schrieb Emily Deng:
>>>>> When the job is already signaled, the s_fence is freed. Then it
>>>>> will has null pointer in amdgpu_device_gpu_recover.
>>>> NAK, the s_fence is only set to NULL when the job is destroyed. See
>>>> drm_sched_job_cleanup().
>>> I know it is set to NULL in drm_sched_job_cleanup. But in one case,
>>> when it enter into the amdgpu_device_gpu_recover, it already in
>>> drm_sched_job_cleanup, and at this time, it will go to free job. But
>>> the amdgpu_device_gpu_recover sometimes is faster. At that time, job
>>> is not freed, but s_fence is already NULL.
>
>No, that case can't happen. See here:
>
>> drm_sched_job_cleanup(s_job);
>>
>> amdgpu_ring_priority_put(ring, s_job->s_priority);
>> dma_fence_put(job->fence);
>> amdgpu_sync_free(&job->sync);
>> amdgpu_sync_free(&job->sched_sync);
>> kfree(job);
>
>The job itself is freed up directly after freeing the reference to the s_fence.
>
>So you are just papering over a much bigger problem here. This patch is a
>clear NAK.
>
>Regards,
>Christian.
>
>>>> When you see a job without an s_fence then that means the problem is
>>>> somewhere else.
>>>>
>>>> Regards,
>>>> Christian.
>>>>
>>>>> Signed-off-by: Emily Deng <Emily.Deng@xxxxxxx>
>>>>> ---
>>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
>>>>> drivers/gpu/drm/scheduler/sched_main.c | 11 ++++++-----
>>>>> 2 files changed, 7 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> index e6ce949..5a8f08e 100644
>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>>>>> @@ -4075,7 +4075,7 @@ int amdgpu_device_gpu_recover(struct
>>>> amdgpu_device *adev,
>>>>> *
>>>>> * job->base holds a reference to parent fence
>>>>> */
>>>>> - if (job && job->base.s_fence->parent &&
>>>>> + if (job && job->base.s_fence && job->base.s_fence->parent &&
>>>>> dma_fence_is_signaled(job->base.s_fence->parent))
>>>>> job_signaled = true;
>>>>>
>>>>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
>>>>> b/drivers/gpu/drm/scheduler/sched_main.c
>>>>> index 31809ca..56cc10e 100644
>>>>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>>>>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>>>>> @@ -334,8 +334,8 @@ void drm_sched_increase_karma(struct
>>>> drm_sched_job
>>>>> *bad)
>>>>>
>>>>> spin_lock(&rq->lock);
>>>>> list_for_each_entry_safe(entity, tmp, &rq->entities,
>>>> list) {
>>>>> - if (bad->s_fence->scheduled.context ==
>>>>> - entity->fence_context) {
>>>>> + if (bad->s_fence && (bad->s_fence-
>>>>> scheduled.context ==
>>>>> + entity->fence_context)) {
>>>>> if (atomic_read(&bad->karma) >
>>>>> bad->sched->hang_limit)
>>>>> if (entity->guilty)
>>>>> @@ -376,7 +376,7 @@ void drm_sched_stop(struct drm_gpu_scheduler
>>>> *sched, struct drm_sched_job *bad)
>>>>> * This iteration is thread safe as sched thread is stopped.
>>>>> */
>>>>> list_for_each_entry_safe_reverse(s_job, tmp, &sched-
>>>>> ring_mirror_list, node) {
>>>>> - if (s_job->s_fence->parent &&
>>>>> + if (s_job->s_fence && s_job->s_fence->parent &&
>>>>> dma_fence_remove_callback(s_job->s_fence->parent,
>>>>> &s_job->cb)) {
>>>>> atomic_dec(&sched->hw_rq_count); @@ -395,7
>>> +395,8 @@ void
>>>>> drm_sched_stop(struct drm_gpu_scheduler
>>>> *sched, struct drm_sched_job *bad)
>>>>> *
>>>>> * Job is still alive so fence refcount at least 1
>>>>> */
>>>>> - dma_fence_wait(&s_job->s_fence->finished, false);
>>>>> + if (s_job->s_fence)
>>>>> + dma_fence_wait(&s_job->s_fence->finished,
>>>> false);
>>>>> /*
>>>>> * We must keep bad job alive for later use during @@
>>>> -438,7
>>>>> +439,7 @@ void drm_sched_start(struct drm_gpu_scheduler *sched,
>>>>> +bool
>>>> full_recovery)
>>>>> * GPU recovers can't run in parallel.
>>>>> */
>>>>> list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list,
>>>>> node)
>>>> {
>>>>> - struct dma_fence *fence = s_job->s_fence->parent;
>>>>> + struct dma_fence *fence = s_job->s_fence ? s_job->s_fence-
>>>>> parent :
>>>>> +NULL;
>>>>>
>>>>> atomic_inc(&sched->hw_rq_count);
>>>>>
>>> _______________________________________________
>>> amd-gfx mailing list
>>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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