[PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Jingwen Chen]

[Why]
for bailing job, this commit will delete it from pending list thus the
bailing job will never have a chance to be resubmitted even in advance
tdr mode.

[How]
after embeded hw_fence into amdgpu_job is done, the race condition that
this commit tries to work around is completely solved.So revert this
commit.
This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.

Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
---
 drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
 1 file changed, 27 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index a2a953693b45..31d1176d939f 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct work_struct *work)
 	enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
 
 	sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
-
-	/* Protects against concurrent deletion in drm_sched_get_cleanup_job */
-	spin_lock(&sched->job_list_lock);
 	job = list_first_entry_or_null(&sched->pending_list,
 				       struct drm_sched_job, list);
 
 	if (job) {
-		/*
-		 * Remove the bad job so it cannot be freed by concurrent
-		 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
-		 * is parked at which point it's safe.
-		 */
-		list_del_init(&job->list);
-		spin_unlock(&sched->job_list_lock);
-
 		status = job->sched->ops->timedout_job(job);
 
 		/*
@@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct work_struct *work)
 			job->sched->ops->free_job(job);
 			sched->free_guilty = false;
 		}
-	} else {
-		spin_unlock(&sched->job_list_lock);
 	}
 
 	if (status != DRM_GPU_SCHED_STAT_ENODEV) {
@@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
 
 	kthread_park(sched->thread);
 
-	/*
-	 * Reinsert back the bad job here - now it's safe as
-	 * drm_sched_get_cleanup_job cannot race against us and release the
-	 * bad job at this point - we parked (waited for) any in progress
-	 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
-	 * now until the scheduler thread is unparked.
-	 */
-	if (bad && bad->sched == sched)
-		/*
-		 * Add at the head of the queue to reflect it was the earliest
-		 * job extracted.
-		 */
-		list_add(&bad->list, &sched->pending_list);
-
 	/*
 	 * Iterate the job list from later to  earlier one and either deactive
 	 * their HW callbacks or remove them from pending list if they already
-- 
2.25.1

RE: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Liu, Monk]

[AMD Official Use Only]

Reviewed-by: Monk Liu <monk.liu@amd.com>

Thanks 

------------------------------------------
Monk Liu | Cloud-GPU Core team
------------------------------------------

-----Original Message-----
From: Jingwen Chen <Jingwen.Chen2@amd.com> 
Sent: Tuesday, August 17, 2021 12:28 PM
To: amd-gfx@lists.freedesktop.org
Cc: Liu, Monk <Monk.Liu@amd.com>; Koenig, Christian <Christian.Koenig@amd.com>; Grodzovsky, Andrey <Andrey.Grodzovsky@amd.com>; Chen, JingWen <JingWen.Chen2@amd.com>
Subject: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Why]
for bailing job, this commit will delete it from pending list thus the bailing job will never have a chance to be resubmitted even in advance tdr mode.

[How]
after embeded hw_fence into amdgpu_job is done, the race condition that this commit tries to work around is completely solved.So revert this commit.
This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.

Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
---
 drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
 1 file changed, 27 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index a2a953693b45..31d1176d939f 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct work_struct *work)
 	enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
 
 	sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
-
-	/* Protects against concurrent deletion in drm_sched_get_cleanup_job */
-	spin_lock(&sched->job_list_lock);
 	job = list_first_entry_or_null(&sched->pending_list,
 				       struct drm_sched_job, list);
 
 	if (job) {
-		/*
-		 * Remove the bad job so it cannot be freed by concurrent
-		 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
-		 * is parked at which point it's safe.
-		 */
-		list_del_init(&job->list);
-		spin_unlock(&sched->job_list_lock);
-
 		status = job->sched->ops->timedout_job(job);
 
 		/*
@@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct work_struct *work)
 			job->sched->ops->free_job(job);
 			sched->free_guilty = false;
 		}
-	} else {
-		spin_unlock(&sched->job_list_lock);
 	}
 
 	if (status != DRM_GPU_SCHED_STAT_ENODEV) { @@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
 
 	kthread_park(sched->thread);
 
-	/*
-	 * Reinsert back the bad job here - now it's safe as
-	 * drm_sched_get_cleanup_job cannot race against us and release the
-	 * bad job at this point - we parked (waited for) any in progress
-	 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
-	 * now until the scheduler thread is unparked.
-	 */
-	if (bad && bad->sched == sched)
-		/*
-		 * Add at the head of the queue to reflect it was the earliest
-		 * job extracted.
-		 */
-		list_add(&bad->list, &sched->pending_list);
-
 	/*
 	 * Iterate the job list from later to  earlier one and either deactive
 	 * their HW callbacks or remove them from pending list if they already
--
2.25.1

Re: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Andrey Grodzovsky]

On 2021-08-17 12:28 a.m., Jingwen Chen wrote:
> [Why]
> for bailing job, this commit will delete it from pending list thus the
> bailing job will never have a chance to be resubmitted even in advance
> tdr mode.
>
> [How]
> after embeded hw_fence into amdgpu_job is done, the race condition that
> this commit tries to work around is completely solved.So revert this
> commit.
> This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.


Can you elaborate please how this solves the race ?
As far as I see and  with this patch reverted, in drm_sched_job_timedout
you get a pointer to next job to process in timed out handler, immediately
next this job is actually finished and it's fence signaled, this in turn 
triggers
drm_sched_get_cleanup_job which fetches this job and returns to 
drm_sched_main
which in turn call free_job callabck->...->amdgpu_fence_free which frees 
the job
from the HW dma_fence release callback. After that you proceed with a 
freed job
in timed out handler.

If you could take the HW fence reference from drm_sched_job_timedout before
starting processing then yes, I think it would work.

Andrey


>
> Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
> ---
>   drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
>   1 file changed, 27 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
> index a2a953693b45..31d1176d939f 100644
> --- a/drivers/gpu/drm/scheduler/sched_main.c
> +++ b/drivers/gpu/drm/scheduler/sched_main.c
> @@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct work_struct *work)
>   	enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
>   
>   	sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
> -
> -	/* Protects against concurrent deletion in drm_sched_get_cleanup_job */
> -	spin_lock(&sched->job_list_lock);
>   	job = list_first_entry_or_null(&sched->pending_list,
>   				       struct drm_sched_job, list);
>   
>   	if (job) {
> -		/*
> -		 * Remove the bad job so it cannot be freed by concurrent
> -		 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
> -		 * is parked at which point it's safe.
> -		 */
> -		list_del_init(&job->list);
> -		spin_unlock(&sched->job_list_lock);
> -
>   		status = job->sched->ops->timedout_job(job);
>   
>   		/*
> @@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct work_struct *work)
>   			job->sched->ops->free_job(job);
>   			sched->free_guilty = false;
>   		}
> -	} else {
> -		spin_unlock(&sched->job_list_lock);
>   	}
>   
>   	if (status != DRM_GPU_SCHED_STAT_ENODEV) {
> @@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
>   
>   	kthread_park(sched->thread);
>   
> -	/*
> -	 * Reinsert back the bad job here - now it's safe as
> -	 * drm_sched_get_cleanup_job cannot race against us and release the
> -	 * bad job at this point - we parked (waited for) any in progress
> -	 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
> -	 * now until the scheduler thread is unparked.
> -	 */
> -	if (bad && bad->sched == sched)
> -		/*
> -		 * Add at the head of the queue to reflect it was the earliest
> -		 * job extracted.
> -		 */
> -		list_add(&bad->list, &sched->pending_list);
> -
>   	/*
>   	 * Iterate the job list from later to  earlier one and either deactive
>   	 * their HW callbacks or remove them from pending list if they already

Re: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Christian König]

Am 17.08.21 um 15:37 schrieb Andrey Grodzovsky:
> On 2021-08-17 12:28 a.m., Jingwen Chen wrote:
>> [Why]
>> for bailing job, this commit will delete it from pending list thus the
>> bailing job will never have a chance to be resubmitted even in advance
>> tdr mode.
>>
>> [How]
>> after embeded hw_fence into amdgpu_job is done, the race condition that
>> this commit tries to work around is completely solved.So revert this
>> commit.
>> This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.
>
>
> Can you elaborate please how this solves the race ?
> As far as I see and  with this patch reverted, in drm_sched_job_timedout
> you get a pointer to next job to process in timed out handler, 
> immediately
> next this job is actually finished and it's fence signaled, this in 
> turn triggers
> drm_sched_get_cleanup_job which fetches this job and returns to 
> drm_sched_main
> which in turn call free_job callabck->...->amdgpu_fence_free which 
> frees the job
> from the HW dma_fence release callback. After that you proceed with a 
> freed job
> in timed out handler.
>
> If you could take the HW fence reference from drm_sched_job_timedout 
> before
> starting processing then yes, I think it would work.

Yes, precisely that's what I had in mind as well and seems to be missing 
from this patch.

Regards,
Christian.

>
> Andrey
>
>
>>
>> Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
>> ---
>>   drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
>>   1 file changed, 27 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c 
>> b/drivers/gpu/drm/scheduler/sched_main.c
>> index a2a953693b45..31d1176d939f 100644
>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>> @@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct 
>> work_struct *work)
>>       enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
>>         sched = container_of(work, struct drm_gpu_scheduler, 
>> work_tdr.work);
>> -
>> -    /* Protects against concurrent deletion in 
>> drm_sched_get_cleanup_job */
>> -    spin_lock(&sched->job_list_lock);
>>       job = list_first_entry_or_null(&sched->pending_list,
>>                          struct drm_sched_job, list);
>>         if (job) {
>> -        /*
>> -         * Remove the bad job so it cannot be freed by concurrent
>> -         * drm_sched_cleanup_jobs. It will be reinserted back after 
>> sched->thread
>> -         * is parked at which point it's safe.
>> -         */
>> -        list_del_init(&job->list);
>> -        spin_unlock(&sched->job_list_lock);
>> -
>>           status = job->sched->ops->timedout_job(job);
>>             /*
>> @@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct 
>> work_struct *work)
>>               job->sched->ops->free_job(job);
>>               sched->free_guilty = false;
>>           }
>> -    } else {
>> -        spin_unlock(&sched->job_list_lock);
>>       }
>>         if (status != DRM_GPU_SCHED_STAT_ENODEV) {
>> @@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler 
>> *sched, struct drm_sched_job *bad)
>>         kthread_park(sched->thread);
>>   -    /*
>> -     * Reinsert back the bad job here - now it's safe as
>> -     * drm_sched_get_cleanup_job cannot race against us and release the
>> -     * bad job at this point - we parked (waited for) any in progress
>> -     * (earlier) cleanups and drm_sched_get_cleanup_job will not be 
>> called
>> -     * now until the scheduler thread is unparked.
>> -     */
>> -    if (bad && bad->sched == sched)
>> -        /*
>> -         * Add at the head of the queue to reflect it was the earliest
>> -         * job extracted.
>> -         */
>> -        list_add(&bad->list, &sched->pending_list);
>> -
>>       /*
>>        * Iterate the job list from later to  earlier one and either 
>> deactive
>>        * their HW callbacks or remove them from pending list if they 
>> already

Re: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Jingwen Chen]

On Tue Aug 17, 2021 at 03:43:58PM +0200, Christian König wrote:
> 
> 
> Am 17.08.21 um 15:37 schrieb Andrey Grodzovsky:
> > On 2021-08-17 12:28 a.m., Jingwen Chen wrote:
> > > [Why]
> > > for bailing job, this commit will delete it from pending list thus the
> > > bailing job will never have a chance to be resubmitted even in advance
> > > tdr mode.
> > > 
> > > [How]
> > > after embeded hw_fence into amdgpu_job is done, the race condition that
> > > this commit tries to work around is completely solved.So revert this
> > > commit.
> > > This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.
> > 
> > 
> > Can you elaborate please how this solves the race ?
> > As far as I see and  with this patch reverted, in drm_sched_job_timedout
> > you get a pointer to next job to process in timed out handler,
> > immediately
> > next this job is actually finished and it's fence signaled, this in turn
> > triggers
> > drm_sched_get_cleanup_job which fetches this job and returns to
Hi Andrey,

if drm_sched_job_timedout is triggered first, drm_sched_get_cleanup_job will return
NULL when the timeout worker is running according to this code:
	if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
	    !cancel_delayed_work(&sched->work_tdr)) ||
	    kthread_should_park())
		return NULL;

But yes a dma_fence_get(job->s_fence->parent) is needed before
processing timedout_job. When the bad job is signaled just before
processing, the amdgpu_fence_free can be triggered by the dma_fence_put() of HW fence.
And if I'm understanding this race condition correctly, the spin_lock is
still needed here to avoid the drm_sched_get_cleanup_job get the
spin_lock first and then enter the tdr work.
> > drm_sched_main
> > which in turn call free_job callabck->...->amdgpu_fence_free which frees
> > the job
> > from the HW dma_fence release callback. After that you proceed with a
> > freed job
> > in timed out handler.
> > 
> > If you could take the HW fence reference from drm_sched_job_timedout
> > before
> > starting processing then yes, I think it would work.
> 
> Yes, precisely that's what I had in mind as well and seems to be missing
> from this patch.
> 
> Regards,
> Christian.
> 
> > 
> > Andrey
> > 
> > 
> > > 
> > > Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
> > > ---
> > >   drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
> > >   1 file changed, 27 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c
> > > b/drivers/gpu/drm/scheduler/sched_main.c
> > > index a2a953693b45..31d1176d939f 100644
> > > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > > @@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct
> > > work_struct *work)
> > >       enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
> > >         sched = container_of(work, struct drm_gpu_scheduler,
> > > work_tdr.work);
> > > -
> > > -    /* Protects against concurrent deletion in
> > > drm_sched_get_cleanup_job */
> > > -    spin_lock(&sched->job_list_lock);
> > >       job = list_first_entry_or_null(&sched->pending_list,
> > >                          struct drm_sched_job, list);
> > >         if (job) {
> > > -        /*
> > > -         * Remove the bad job so it cannot be freed by concurrent
> > > -         * drm_sched_cleanup_jobs. It will be reinserted back after
> > > sched->thread
> > > -         * is parked at which point it's safe.
> > > -         */
> > > -        list_del_init(&job->list);
> > > -        spin_unlock(&sched->job_list_lock);
> > > -
> > >           status = job->sched->ops->timedout_job(job);
> > >             /*
> > > @@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct
> > > work_struct *work)
> > >               job->sched->ops->free_job(job);
> > >               sched->free_guilty = false;
> > >           }
> > > -    } else {
> > > -        spin_unlock(&sched->job_list_lock);
> > >       }
> > >         if (status != DRM_GPU_SCHED_STAT_ENODEV) {
> > > @@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler
> > > *sched, struct drm_sched_job *bad)
> > >         kthread_park(sched->thread);
> > >   -    /*
> > > -     * Reinsert back the bad job here - now it's safe as
> > > -     * drm_sched_get_cleanup_job cannot race against us and release the
> > > -     * bad job at this point - we parked (waited for) any in progress
> > > -     * (earlier) cleanups and drm_sched_get_cleanup_job will not be
> > > called
> > > -     * now until the scheduler thread is unparked.
> > > -     */
> > > -    if (bad && bad->sched == sched)
> > > -        /*
> > > -         * Add at the head of the queue to reflect it was the earliest
> > > -         * job extracted.
> > > -         */
> > > -        list_add(&bad->list, &sched->pending_list);
> > > -
> > >       /*
> > >        * Iterate the job list from later to  earlier one and either
> > > deactive
> > >        * their HW callbacks or remove them from pending list if they
> > > already
> 

Re: [PATCH] Revert "drm/scheduler: Avoid accessing freed bad job."

[Jingwen Chen]

Sorry, just get what you mean, will submit a v2 patch.

On Wed Aug 18, 2021 at 04:08:37PM +0800, Jingwen Chen wrote:
> On Tue Aug 17, 2021 at 03:43:58PM +0200, Christian König wrote:
> > 
> > 
> > Am 17.08.21 um 15:37 schrieb Andrey Grodzovsky:
> > > On 2021-08-17 12:28 a.m., Jingwen Chen wrote:
> > > > [Why]
> > > > for bailing job, this commit will delete it from pending list thus the
> > > > bailing job will never have a chance to be resubmitted even in advance
> > > > tdr mode.
> > > > 
> > > > [How]
> > > > after embeded hw_fence into amdgpu_job is done, the race condition that
> > > > this commit tries to work around is completely solved.So revert this
> > > > commit.
> > > > This reverts commit 135517d3565b48f4def3b1b82008bc17eb5d1c90.
> > > 
> > > 
> > > Can you elaborate please how this solves the race ?
> > > As far as I see and  with this patch reverted, in drm_sched_job_timedout
> > > you get a pointer to next job to process in timed out handler,
> > > immediately
> > > next this job is actually finished and it's fence signaled, this in turn
> > > triggers
> > > drm_sched_get_cleanup_job which fetches this job and returns to
> Hi Andrey,
> 
> if drm_sched_job_timedout is triggered first, drm_sched_get_cleanup_job will return
> NULL when the timeout worker is running according to this code:
> 	if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
> 	    !cancel_delayed_work(&sched->work_tdr)) ||
> 	    kthread_should_park())
> 		return NULL;
> 
> But yes a dma_fence_get(job->s_fence->parent) is needed before
> processing timedout_job. When the bad job is signaled just before
> processing, the amdgpu_fence_free can be triggered by the dma_fence_put() of HW fence.
> And if I'm understanding this race condition correctly, the spin_lock is
> still needed here to avoid the drm_sched_get_cleanup_job get the
> spin_lock first and then enter the tdr work.
> > > drm_sched_main
> > > which in turn call free_job callabck->...->amdgpu_fence_free which frees
> > > the job
> > > from the HW dma_fence release callback. After that you proceed with a
> > > freed job
> > > in timed out handler.
> > > 
> > > If you could take the HW fence reference from drm_sched_job_timedout
> > > before
> > > starting processing then yes, I think it would work.
> > 
> > Yes, precisely that's what I had in mind as well and seems to be missing
> > from this patch.
> > 
> > Regards,
> > Christian.
> > 
> > > 
> > > Andrey
> > > 
> > > 
> > > > 
> > > > Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
> > > > ---
> > > >   drivers/gpu/drm/scheduler/sched_main.c | 27 --------------------------
> > > >   1 file changed, 27 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/scheduler/sched_main.c
> > > > b/drivers/gpu/drm/scheduler/sched_main.c
> > > > index a2a953693b45..31d1176d939f 100644
> > > > --- a/drivers/gpu/drm/scheduler/sched_main.c
> > > > +++ b/drivers/gpu/drm/scheduler/sched_main.c
> > > > @@ -317,21 +317,10 @@ static void drm_sched_job_timedout(struct
> > > > work_struct *work)
> > > >       enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
> > > >         sched = container_of(work, struct drm_gpu_scheduler,
> > > > work_tdr.work);
> > > > -
> > > > -    /* Protects against concurrent deletion in
> > > > drm_sched_get_cleanup_job */
> > > > -    spin_lock(&sched->job_list_lock);
> > > >       job = list_first_entry_or_null(&sched->pending_list,
> > > >                          struct drm_sched_job, list);
> > > >         if (job) {
> > > > -        /*
> > > > -         * Remove the bad job so it cannot be freed by concurrent
> > > > -         * drm_sched_cleanup_jobs. It will be reinserted back after
> > > > sched->thread
> > > > -         * is parked at which point it's safe.
> > > > -         */
> > > > -        list_del_init(&job->list);
> > > > -        spin_unlock(&sched->job_list_lock);
> > > > -
> > > >           status = job->sched->ops->timedout_job(job);
> > > >             /*
> > > > @@ -342,8 +331,6 @@ static void drm_sched_job_timedout(struct
> > > > work_struct *work)
> > > >               job->sched->ops->free_job(job);
> > > >               sched->free_guilty = false;
> > > >           }
> > > > -    } else {
> > > > -        spin_unlock(&sched->job_list_lock);
> > > >       }
> > > >         if (status != DRM_GPU_SCHED_STAT_ENODEV) {
> > > > @@ -392,20 +379,6 @@ void drm_sched_stop(struct drm_gpu_scheduler
> > > > *sched, struct drm_sched_job *bad)
> > > >         kthread_park(sched->thread);
> > > >   -    /*
> > > > -     * Reinsert back the bad job here - now it's safe as
> > > > -     * drm_sched_get_cleanup_job cannot race against us and release the
> > > > -     * bad job at this point - we parked (waited for) any in progress
> > > > -     * (earlier) cleanups and drm_sched_get_cleanup_job will not be
> > > > called
> > > > -     * now until the scheduler thread is unparked.
> > > > -     */
> > > > -    if (bad && bad->sched == sched)
> > > > -        /*
> > > > -         * Add at the head of the queue to reflect it was the earliest
> > > > -         * job extracted.
> > > > -         */
> > > > -        list_add(&bad->list, &sched->pending_list);
> > > > -
> > > >       /*
> > > >        * Iterate the job list from later to  earlier one and either
> > > > deactive
> > > >        * their HW callbacks or remove them from pending list if they
> > > > already
> >