Re: [PATCH v3] drm/scheduler re-insert Bailing job to avoid memleak

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There are a few issues here like - how u handle non guilty singnaled jobs
in drm_sched_stop, currently looks like you don't call put for them
and just explicitly free them as before. Also sched->free_guilty
seems useless with the new approach. Do we even need the cleanup
mechanism at drm_sched_get_cleanup_job with this approach...

But first - We need Christian to express his opinion on this since
I think he opposed refcounting jobs and that we should concentrate on
fences instead.

Christian - can you chime in here ?

Andrey

On 2021-03-25 5:51 a.m., Zhang, Jack (Jian) wrote:
[AMD Official Use Only - Internal Distribution Only]


Hi, Andrey

Thank you for your good opinions.

I literally agree with you that the refcount could solve the get_clean_up_up cocurrent job gracefully, and no need to re-insert the

job back anymore.

I quickly made a draft for this idea as follows:

How do you like it? I will start implement to it after I got your acknowledge.

Thanks,

Jack

+void drm_job_get(struct drm_sched_job *s_job)

+{

+       kref_get(&s_job->refcount);

+}

+

+void drm_job_do_release(struct kref *ref)

+{

+       struct drm_sched_job *s_job;

+       struct drm_gpu_scheduler *sched;

+

+       s_job = container_of(ref, struct drm_sched_job, refcount);

+       sched = s_job->sched;

+       sched->ops->free_job(s_job);

+}

+

+void drm_job_put(struct drm_sched_job *s_job)

+{

+       kref_put(&s_job->refcount, drm_job_do_release);

+}

+

static void drm_sched_job_begin(struct drm_sched_job *s_job)

{

         struct drm_gpu_scheduler *sched = s_job->sched;

+       kref_init(&s_job->refcount);

+       drm_job_get(s_job);

         spin_lock(&sched->job_list_lock);

         list_add_tail(&s_job->node, &sched->ring_mirror_list);

         drm_sched_start_timeout(sched);

@@ -294,17 +316,16 @@ static void drm_sched_job_timedout(struct work_struct *work)

                 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread

                  * is parked at which point it's safe.

                  */

-               list_del_init(&job->node);

+               drm_job_get(job);

                 spin_unlock(&sched->job_list_lock);

                 job->sched->ops->timedout_job(job);

-

+               drm_job_put(job);

                 /*

                 * Guilty job did complete and hence needs to be manually removed

                  * See drm_sched_stop doc.

                  */

                 if (sched->free_guilty) {

-                       job->sched->ops->free_job(job);

                         sched->free_guilty = false;

                 }

         } else {

@@ -355,20 +376,6 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)

-       /*

-        * 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->node, &sched->ring_mirror_list);

-

         /*

         * Iterate the job list from later to  earlier one and either deactive

         * their HW callbacks or remove them from mirror list if they already

@@ -774,7 +781,7 @@ static int drm_sched_main(void *param)

                                          kthread_should_stop());

                 if (cleanup_job) {

-                       sched->ops->free_job(cleanup_job);

+                       drm_job_put(cleanup_job);

                         /* queue timeout for next job */

                         drm_sched_start_timeout(sched);

                 }

diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h

index 5a1f068af1c2..b80513eec90f 100644

--- a/include/drm/gpu_scheduler.h

+++ b/include/drm/gpu_scheduler.h

@@ -188,6 +188,7 @@ struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);

   * to schedule the job.

   */

struct drm_sched_job {

+       struct kref                     refcount;

         struct spsc_node                queue_node;

         struct drm_gpu_scheduler        *sched;

         struct drm_sched_fence          *s_fence;

@@ -198,6 +199,7 @@ struct drm_sched_job {

         enum drm_sched_priority         s_priority;

         struct drm_sched_entity  *entity;

         struct dma_fence_cb             cb;

+

};

*From:* Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>
*Sent:* Friday, March 19, 2021 12:17 AM
*To:* Zhang, Jack (Jian) <Jack.Zhang1@xxxxxxx>; Christian König <ckoenig.leichtzumerken@xxxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; amd-gfx@xxxxxxxxxxxxxxxxxxxxx; Koenig, Christian <Christian.Koenig@xxxxxxx>; Liu, Monk <Monk.Liu@xxxxxxx>; Deng, Emily <Emily.Deng@xxxxxxx>; Rob Herring <robh@xxxxxxxxxx>; Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>; Steven Price <steven.price@xxxxxxx> *Subject:* Re: [PATCH v3] drm/scheduler re-insert Bailing job to avoid memleak

On 2021-03-18 6:41 a.m., Zhang, Jack (Jian) wrote:

    [AMD Official Use Only - Internal Distribution Only]

    Hi, Andrey

    Let me summarize the background of this patch:

    In TDR resubmit step “amdgpu_device_recheck_guilty_jobs,

    It will submit first jobs of each ring and do guilty job re-check.

    At that point, We had to make sure each job is in the mirror list(or
    re-inserted back already).

    But we found the current code never re-insert the job to mirror list
    in the 2^nd , 3^rd job_timeout thread(Bailing TDR thread).

    This not only will cause memleak of the bailing jobs. What’s more
    important, the 1^st tdr thread can never iterate the bailing job and
    set its guilty status to a correct status.

    Therefore, we had to re-insert the job(or even not delete node) for
    bailing job.

    For the above V3 patch, the racing condition in my mind is:

    we cannot make sure all bailing jobs are finished before we do
    amdgpu_device_recheck_guilty_jobs.

Yes,that race i missed - so you say that for 2nd, baling thread who extracted the job, even if he reinsert it right away back after driver callback return DRM_GPU_SCHED_STAT_BAILING, there is small time slot where the job is not in mirror list and so the 1st TDR might miss it and not find that  2nd job is the actual guilty job, right ? But, still this job will get back into mirror list, and since it's really the bad job, it will never signal completion and so on the next timeout cycle it will be caught (of course there is a starvation scenario here if more TDRs kick in and it bails out again but this is really unlikely).

    Based on this insight, I think we have two options to solve this issue:

     1. Skip delete node in tdr thread2, thread3, 4 … (using mutex or
        atomic variable)
     2. Re-insert back bailing job, and meanwhile use semaphore in each
        tdr thread to keep the sequence as expected and ensure each job
        is in the mirror list when do resubmit step.

    For Option1, logic is simpler and we need only one global atomic
    variable:

    What do you think about this plan?

    Option1 should look like the following logic:

    +static atomic_t in_reset;             //a global atomic var for
    synchronization

    static void drm_sched_process_job(struct dma_fence *f, struct
    dma_fence_cb *cb);

      /**

    @@ -295,6 +296,12 @@ static void drm_sched_job_timedout(struct
    work_struct *work)

                      * drm_sched_cleanup_jobs. It will be reinserted
    back after sched->thread

                      * is parked at which point it's safe.

                      */

    +               if (atomic_cmpxchg(&in_reset, 0, 1) != 0) {  //skip
    delete node if it’s thead1,2,3,….

    +                       spin_unlock(&sched->job_list_lock);

    +                       drm_sched_start_timeout(sched);

    +                       return;

    +               }

    +

                     list_del_init(&job->node);

                     spin_unlock(&sched->job_list_lock);

    @@ -320,6 +327,7 @@ static void drm_sched_job_timedout(struct
    work_struct *work)

             spin_lock(&sched->job_list_lock);

             drm_sched_start_timeout(sched);

             spin_unlock(&sched->job_list_lock);

    +       atomic_set(&in_reset, 0); //reset in_reset when the first
    thread finished tdr

    }

Technically looks like it should work as you don't access the job pointer any longer and so no risk that if signaled it will be freed by drm_sched_get_cleanup_job but,you can't just use one global variable an by this bailing from TDR when different drivers run their TDR threads in parallel, and even for amdgpu, if devices in different XGMI hives or 2 independent devices in non XGMI setup. There should be defined some kind of GPU reset group structure on drm_scheduler level for which this variable would be used.

P.S I wonder why we can't just ref-count the job so that even if drm_sched_get_cleanup_job would delete it before we had a chance to stop the scheduler thread, we wouldn't crash. This would avoid all the dance with deletion and reinsertion.

Andrey

    Thanks,

    Jack

    *From:* amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx>
    <mailto:amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> *On Behalf Of *Zhang,
    Jack (Jian)
    *Sent:* Wednesday, March 17, 2021 11:11 PM
    *To:* Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
    <mailto:ckoenig.leichtzumerken@xxxxxxxxx>;
    dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>;
    amd-gfx@xxxxxxxxxxxxxxxxxxxxx
    <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>; Koenig, Christian
    <Christian.Koenig@xxxxxxx> <mailto:Christian.Koenig@xxxxxxx>; Liu,
    Monk <Monk.Liu@xxxxxxx> <mailto:Monk.Liu@xxxxxxx>; Deng, Emily
    <Emily.Deng@xxxxxxx> <mailto:Emily.Deng@xxxxxxx>; Rob Herring
    <robh@xxxxxxxxxx> <mailto:robh@xxxxxxxxxx>; Tomeu Vizoso
    <tomeu.vizoso@xxxxxxxxxxxxx> <mailto:tomeu.vizoso@xxxxxxxxxxxxx>;
    Steven Price <steven.price@xxxxxxx> <mailto:steven.price@xxxxxxx>;
    Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>
    <mailto:Andrey.Grodzovsky@xxxxxxx>
    *Subject:* Re: [PATCH v3] drm/scheduler re-insert Bailing job to
    avoid memleak

    [AMD Official Use Only - Internal Distribution Only]

    [AMD Official Use Only - Internal Distribution Only]

    Hi,Andrey,

    Good catch,I will expore this corner case and give feedback soon~

    Best,

    Jack

    ------------------------------------------------------------------------

    *From:*Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx
    <mailto:Andrey.Grodzovsky@xxxxxxx>>
    *Sent:* Wednesday, March 17, 2021 10:50:59 PM
    *To:* Christian König <ckoenig.leichtzumerken@xxxxxxxxx
    <mailto:ckoenig.leichtzumerken@xxxxxxxxx>>; Zhang, Jack (Jian)
    <Jack.Zhang1@xxxxxxx <mailto:Jack.Zhang1@xxxxxxx>>;
    dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>
    <dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>>;
    amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
    <amd-gfx@xxxxxxxxxxxxxxxxxxxxx
    <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>>; Koenig, Christian
    <Christian.Koenig@xxxxxxx <mailto:Christian.Koenig@xxxxxxx>>; Liu,
    Monk <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>; Deng, Emily
    <Emily.Deng@xxxxxxx <mailto:Emily.Deng@xxxxxxx>>; Rob Herring
    <robh@xxxxxxxxxx <mailto:robh@xxxxxxxxxx>>; Tomeu Vizoso
    <tomeu.vizoso@xxxxxxxxxxxxx <mailto:tomeu.vizoso@xxxxxxxxxxxxx>>;
    Steven Price <steven.price@xxxxxxx <mailto:steven.price@xxxxxxx>>
    *Subject:* Re: [PATCH v3] drm/scheduler re-insert Bailing job to
    avoid memleak

    I actually have a race condition concern here - see bellow -

    On 2021-03-17 3:43 a.m., Christian König wrote:
     > I was hoping Andrey would take a look since I'm really busy with
    other
     > work right now.
     >
     > Regards,
     > Christian.
     >
     > Am 17.03.21 um 07:46 schrieb Zhang, Jack (Jian):
     >> Hi, Andrey/Crhistian and Team,
     >>
     >> I didn't receive the reviewer's message from maintainers on
    panfrost
     >> driver for several days.
     >> Due to this patch is urgent for my current working project.
     >> Would you please help to give some review ideas?
     >>
     >> Many Thanks,
     >> Jack
     >> -----Original Message-----
     >> From: Zhang, Jack (Jian)
     >> Sent: Tuesday, March 16, 2021 3:20 PM
     >> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>;
    amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>;
     >> Koenig, Christian <Christian.Koenig@xxxxxxx
    <mailto:Christian.Koenig@xxxxxxx>>; Grodzovsky, Andrey
     >> <Andrey.Grodzovsky@xxxxxxx <mailto:Andrey.Grodzovsky@xxxxxxx>>;
    Liu, Monk <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>; Deng,
     >> Emily <Emily.Deng@xxxxxxx <mailto:Emily.Deng@xxxxxxx>>; Rob
    Herring <robh@xxxxxxxxxx <mailto:robh@xxxxxxxxxx>>; Tomeu
     >> Vizoso <tomeu.vizoso@xxxxxxxxxxxxx
    <mailto:tomeu.vizoso@xxxxxxxxxxxxx>>; Steven Price
    <steven.price@xxxxxxx <mailto:steven.price@xxxxxxx>>
     >> Subject: RE: [PATCH v3] drm/scheduler re-insert Bailing job to
    avoid
     >> memleak
     >>
     >> [AMD Public Use]
     >>
     >> Ping
     >>
     >> -----Original Message-----
     >> From: Zhang, Jack (Jian)
     >> Sent: Monday, March 15, 2021 1:24 PM
     >> To: Jack Zhang <Jack.Zhang1@xxxxxxx <mailto:Jack.Zhang1@xxxxxxx>>;
     >> dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>;
    amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>;
     >> Koenig, Christian <Christian.Koenig@xxxxxxx
    <mailto:Christian.Koenig@xxxxxxx>>; Grodzovsky, Andrey
     >> <Andrey.Grodzovsky@xxxxxxx <mailto:Andrey.Grodzovsky@xxxxxxx>>;
    Liu, Monk <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>; Deng,
     >> Emily <Emily.Deng@xxxxxxx <mailto:Emily.Deng@xxxxxxx>>; Rob
    Herring <robh@xxxxxxxxxx <mailto:robh@xxxxxxxxxx>>; Tomeu
     >> Vizoso <tomeu.vizoso@xxxxxxxxxxxxx
    <mailto:tomeu.vizoso@xxxxxxxxxxxxx>>; Steven Price
    <steven.price@xxxxxxx <mailto:steven.price@xxxxxxx>>
     >> Subject: RE: [PATCH v3] drm/scheduler re-insert Bailing job to
    avoid
     >> memleak
     >>
     >> [AMD Public Use]
     >>
     >> Hi, Rob/Tomeu/Steven,
     >>
     >> Would you please help to review this patch for panfrost driver?
     >>
     >> Thanks,
     >> Jack Zhang
     >>
     >> -----Original Message-----
     >> From: Jack Zhang <Jack.Zhang1@xxxxxxx <mailto:Jack.Zhang1@xxxxxxx>>
     >> Sent: Monday, March 15, 2021 1:21 PM
     >> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx
    <mailto:dri-devel@xxxxxxxxxxxxxxxxxxxxx>;
    amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>;
     >> Koenig, Christian <Christian.Koenig@xxxxxxx
    <mailto:Christian.Koenig@xxxxxxx>>; Grodzovsky, Andrey
     >> <Andrey.Grodzovsky@xxxxxxx <mailto:Andrey.Grodzovsky@xxxxxxx>>;
    Liu, Monk <Monk.Liu@xxxxxxx <mailto:Monk.Liu@xxxxxxx>>; Deng,
     >> Emily <Emily.Deng@xxxxxxx <mailto:Emily.Deng@xxxxxxx>>
     >> Cc: Zhang, Jack (Jian) <Jack.Zhang1@xxxxxxx
    <mailto:Jack.Zhang1@xxxxxxx>>
     >> Subject: [PATCH v3] drm/scheduler re-insert Bailing job to avoid
    memleak
     >>
     >> re-insert Bailing jobs to avoid memory leak.
     >>
     >> V2: move re-insert step to drm/scheduler logic
     >> V3: add panfrost's return value for bailing jobs in case it hits
    the
     >> memleak issue.
     >>
     >> Signed-off-by: Jack Zhang <Jack.Zhang1@xxxxxxx
    <mailto:Jack.Zhang1@xxxxxxx>>
     >> ---
     >>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 +++-
     >>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c    | 8 ++++++--
     >>   drivers/gpu/drm/panfrost/panfrost_job.c    | 4 ++--
     >>   drivers/gpu/drm/scheduler/sched_main.c     | 8 +++++++-
     >>   include/drm/gpu_scheduler.h                | 1 +
     >>   5 files changed, 19 insertions(+), 6 deletions(-)
     >>
     >> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
     >> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
     >> index 79b9cc73763f..86463b0f936e 100644
     >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
     >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
     >> @@ -4815,8 +4815,10 @@ int amdgpu_device_gpu_recover(struct
     >> amdgpu_device *adev,
     >>                       job ? job->base.id : -1);
     >>             /* even we skipped this reset, still need to set the
    job
     >> to guilty */
     >> -        if (job)
     >> +        if (job) {
     >>               drm_sched_increase_karma(&job->base);
     >> +            r = DRM_GPU_SCHED_STAT_BAILING;
     >> +        }
     >>           goto skip_recovery;
     >>       }
     >>   diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
     >> b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
     >> index 759b34799221..41390bdacd9e 100644
     >> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
     >> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
     >> @@ -34,6 +34,7 @@ static enum drm_gpu_sched_stat
     >> amdgpu_job_timedout(struct drm_sched_job *s_job)
     >>       struct amdgpu_job *job = to_amdgpu_job(s_job);
     >>       struct amdgpu_task_info ti;
     >>       struct amdgpu_device *adev = ring->adev;
     >> +    int ret;
     >>         memset(&ti, 0, sizeof(struct amdgpu_task_info));
     >>   @@ -52,8 +53,11 @@ static enum drm_gpu_sched_stat
     >> amdgpu_job_timedout(struct drm_sched_job *s_job)
     >>             ti.process_name, ti.tgid, ti.task_name, ti.pid);
     >>         if (amdgpu_device_should_recover_gpu(ring->adev)) {
     >> -        amdgpu_device_gpu_recover(ring->adev, job);
     >> -        return DRM_GPU_SCHED_STAT_NOMINAL;
     >> +        ret = amdgpu_device_gpu_recover(ring->adev, job);
     >> +        if (ret == DRM_GPU_SCHED_STAT_BAILING)
     >> +            return DRM_GPU_SCHED_STAT_BAILING;
     >> +        else
     >> +            return DRM_GPU_SCHED_STAT_NOMINAL;
     >>       } else {
     >>           drm_sched_suspend_timeout(&ring->sched);
     >>           if (amdgpu_sriov_vf(adev))
     >> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c
     >> b/drivers/gpu/drm/panfrost/panfrost_job.c
     >> index 6003cfeb1322..e2cb4f32dae1 100644
     >> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
     >> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
     >> @@ -444,7 +444,7 @@ static enum drm_gpu_sched_stat
     >> panfrost_job_timedout(struct drm_sched_job
     >>        * spurious. Bail out.
     >>        */
     >>       if (dma_fence_is_signaled(job->done_fence))
     >> -        return DRM_GPU_SCHED_STAT_NOMINAL;
     >> +        return DRM_GPU_SCHED_STAT_BAILING;
     >>         dev_err(pfdev->dev, "gpu sched timeout, js=%d, config=0x%x,
     >> status=0x%x, head=0x%x, tail=0x%x, sched_job=%p",
     >>           js,
     >> @@ -456,7 +456,7 @@ static enum drm_gpu_sched_stat
     >> panfrost_job_timedout(struct drm_sched_job
     >>         /* Scheduler is already stopped, nothing to do. */
     >>       if (!panfrost_scheduler_stop(&pfdev->js->queue[js],
    sched_job))
     >> -        return DRM_GPU_SCHED_STAT_NOMINAL;
     >> +        return DRM_GPU_SCHED_STAT_BAILING;
     >>         /* Schedule a reset if there's no reset in progress. */
     >>       if (!atomic_xchg(&pfdev->reset.pending, 1)) diff --git
     >> a/drivers/gpu/drm/scheduler/sched_main.c
     >> b/drivers/gpu/drm/scheduler/sched_main.c
     >> index 92d8de24d0a1..a44f621fb5c4 100644
     >> --- a/drivers/gpu/drm/scheduler/sched_main.c
     >> +++ b/drivers/gpu/drm/scheduler/sched_main.c
     >> @@ -314,6 +314,7 @@ static void drm_sched_job_timedout(struct
     >> work_struct *work)  {
     >>       struct drm_gpu_scheduler *sched;
     >>       struct drm_sched_job *job;
     >> +    int ret;
     >>         sched = container_of(work, struct drm_gpu_scheduler,
     >> work_tdr.work);
     >>   @@ -331,8 +332,13 @@ static void drm_sched_job_timedout(struct
     >> work_struct *work)
     >>           list_del_init(&job->list);
     >>           spin_unlock(&sched->job_list_lock);
     >>   -        job->sched->ops->timedout_job(job);
     >> +        ret = job->sched->ops->timedout_job(job);
     >>   +        if (ret == DRM_GPU_SCHED_STAT_BAILING) {
     >> +            spin_lock(&sched->job_list_lock);
     >> +            list_add(&job->node, &sched->ring_mirror_list);
     >> +            spin_unlock(&sched->job_list_lock);
     >> +        }


    At this point we don't hold GPU reset locks anymore, and so we could
    be racing against another TDR thread from another scheduler ring of
    same
    device
    or another XGMI hive member. The other thread might be in the middle of
    luckless
    iteration of mirror list (drm_sched_stop, drm_sched_start and
    drm_sched_resubmit)
    and so locking job_list_lock will not help. Looks like it's required to
    take all GPU rest locks
    here.

    Andrey


     >>           /*
     >>            * Guilty job did complete and hence needs to be manually
     >> removed
     >>            * See drm_sched_stop doc.
     >> diff --git a/include/drm/gpu_scheduler.h
     >> b/include/drm/gpu_scheduler.h index 4ea8606d91fe..8093ac2427ef
    100644
     >> --- a/include/drm/gpu_scheduler.h
     >> +++ b/include/drm/gpu_scheduler.h
     >> @@ -210,6 +210,7 @@ enum drm_gpu_sched_stat {
     >>       DRM_GPU_SCHED_STAT_NONE, /* Reserve 0 */
     >>       DRM_GPU_SCHED_STAT_NOMINAL,
     >>       DRM_GPU_SCHED_STAT_ENODEV,
     >> +    DRM_GPU_SCHED_STAT_BAILING,
     >>   };
     >>     /**
     >> --
     >> 2.25.1
     >> _______________________________________________
     >> amd-gfx mailing list
     >> amd-gfx@xxxxxxxxxxxxxxxxxxxxx <mailto:amd-gfx@xxxxxxxxxxxxxxxxxxxxx>
     >>
    https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=04%7C01%7CAndrey.Grodzovsky%40amd.com%7Ce90f30af0f43444c6aea08d8e91860c4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637515638213180413%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=NnLqtz%2BZ8%2BweYwCqRinrfkqmhzibNAF6CYSdVqL6xi0%3D&amp;reserved=0
    <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=04%7C01%7CJack.Zhang1%40amd.com%7C95b2ff206ee74bbe520a08d8e956f5dd%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637515907000888939%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=BGoSfOYiDar8SrpMx%2BsOMWpaMr87bxB%2F9ycu0FhhipA%3D&reserved=0>

     >>
     >

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