From: "Deucher, Alexander" <Alexander.Deucher@amd.com>
To: "Grodzovsky, Andrey" <Andrey.Grodzovsky@amd.com>,
"Deng, Emily" <Emily.Deng@amd.com>
Cc: "steven.price@arm.com" <steven.price@arm.com>,
"amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"Koenig, Christian" <Christian.Koenig@amd.com>
Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Date: Tue, 3 Dec 2019 19:44:30 +0000 [thread overview]
Message-ID: <MWHPR12MB13589D76D1F7D518FE7D6F08F7420@MWHPR12MB1358.namprd12.prod.outlook.com> (raw)
In-Reply-To: <40f1020c-fccf-99f9-33ff-f82ef1f5f360@amd.com>
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[AMD Official Use Only - Internal Distribution Only]
Please go ahead an apply whatever version is necessary for amd-staging-drm-next.
Alex
________________________________
From: Grodzovsky, Andrey <Andrey.Grodzovsky@amd.com>
Sent: Tuesday, December 3, 2019 2:10 PM
To: Deng, Emily <Emily.Deng@amd.com>; Deucher, Alexander <Alexander.Deucher@amd.com>
Cc: dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>; amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; Koenig, Christian <Christian.Koenig@amd.com>; steven.price@arm.com <steven.price@arm.com>
Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Yes - Christian just pushed it to drm-next-misc - I guess Alex/Christian
didn't pull to amd-staging-drm-next yet.
Andrey
On 12/2/19 2:24 PM, Deng, Emily wrote:
> [AMD Official Use Only - Internal Distribution Only]
>
> Hi Andrey,
> Seems this patch is still not in amd-staging-drm-next?
>
> Best wishes
> Emily Deng
>
>
>
>> -----Original Message-----
>> From: Deng, Emily
>> Sent: Tuesday, November 26, 2019 4:41 PM
>> To: Grodzovsky, Andrey <Andrey.Grodzovsky@amd.com>
>> Cc: dri-devel@lists.freedesktop.org; amd-gfx@lists.freedesktop.org; Koenig,
>> Christian <Christian.Koenig@amd.com>; steven.price@arm.com
>> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>>
>> [AMD Official Use Only - Internal Distribution Only]
>>
>> Reviewed-by: Emily Deng <Emily.Deng@amd.com>
>>
>>> -----Original Message-----
>>> From: Grodzovsky, Andrey <Andrey.Grodzovsky@amd.com>
>>> Sent: Tuesday, November 26, 2019 7:37 AM
>>> Cc: dri-devel@lists.freedesktop.org; amd-gfx@lists.freedesktop.org;
>>> Koenig, Christian <Christian.Koenig@amd.com>; Deng, Emily
>>> <Emily.Deng@amd.com>; steven.price@arm.com
>>> Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>>>
>>> Ping
>>>
>>> Andrey
>>>
>>> On 11/25/19 3:51 PM, Andrey Grodzovsky wrote:
>>>> Problem:
>>>> Due to a race between drm_sched_cleanup_jobs in sched thread and
>>>> drm_sched_job_timedout in timeout work there is a possiblity that bad
>>>> job was already freed while still being accessed from the timeout
>>>> thread.
>>>>
>>>> Fix:
>>>> Instead of just peeking at the bad job in the mirror list remove it
>>>> from the list under lock and then put it back later when we are
>>>> garanteed no race with main sched thread is possible which is after
>>>> the thread is parked.
>>>>
>>>> v2: Lock around processing ring_mirror_list in drm_sched_cleanup_jobs.
>>>>
>>>> v3: Rebase on top of drm-misc-next. v2 is not needed anymore as
>>>> drm_sched_get_cleanup_job already has a lock there.
>>>>
>>>> v4: Fix comments to relfect latest code in drm-misc.
>>>>
>>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
>>>> Reviewed-by: Christian König <christian.koenig@amd.com>
>>>> Tested-by: Emily Deng <Emily.Deng@amd.com>
>>>> ---
>>>> drivers/gpu/drm/scheduler/sched_main.c | 27
>>> +++++++++++++++++++++++++++
>>>> 1 file changed, 27 insertions(+)
>>>>
>>>> diff --git a/drivers/gpu/drm/scheduler/sched_main.c
>>>> b/drivers/gpu/drm/scheduler/sched_main.c
>>>> index 6774955..1bf9c40 100644
>>>> --- a/drivers/gpu/drm/scheduler/sched_main.c
>>>> +++ b/drivers/gpu/drm/scheduler/sched_main.c
>>>> @@ -284,10 +284,21 @@ static void drm_sched_job_timedout(struct
>>> work_struct *work)
>>>> unsigned long flags;
>>>>
>>>> sched = container_of(work, struct drm_gpu_scheduler,
>>>> work_tdr.work);
>>>> +
>>>> + /* Protects against concurrent deletion in
>>> drm_sched_get_cleanup_job */
>>>> + spin_lock_irqsave(&sched->job_list_lock, flags);
>>>> job = list_first_entry_or_null(&sched->ring_mirror_list,
>>>> struct drm_sched_job, node);
>>>>
>>>> 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->node);
>>>> + spin_unlock_irqrestore(&sched->job_list_lock, flags);
>>>> +
>>>> job->sched->ops->timedout_job(job);
>>>>
>>>> /*
>>>> @@ -298,6 +309,8 @@ static void drm_sched_job_timedout(struct
>>> work_struct *work)
>>>> job->sched->ops->free_job(job);
>>>> sched->free_guilty = false;
>>>> }
>>>> + } else {
>>>> + spin_unlock_irqrestore(&sched->job_list_lock, flags);
>>>> }
>>>>
>>>> spin_lock_irqsave(&sched->job_list_lock, flags); @@ -370,6 +383,20
>>>> @@ 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->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
>>>> * signaled.
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next prev parent reply other threads:[~2019-12-03 19:44 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-25 20:51 [PATCH v4] drm/scheduler: Avoid accessing freed bad job Andrey Grodzovsky
2019-11-25 20:51 ` Andrey Grodzovsky
2019-11-25 21:44 ` Deng, Emily
2019-11-25 21:44 ` Deng, Emily
2019-11-26 0:09 ` Grodzovsky, Andrey
2019-11-26 0:09 ` Grodzovsky, Andrey
[not found] ` <MWHPR12MB1453C6FC45A83482232CA3EDEA450-Gy0DoCVfaSWZBIDmKHdw+wdYzm3356FpvxpqHgZTriW3zl9H0oFU5g@public.gmane.org>
2019-11-26 15:36 ` Deucher, Alexander
2019-11-26 15:36 ` Deucher, Alexander
2019-11-26 15:37 ` Andrey Grodzovsky
2019-11-26 15:37 ` Andrey Grodzovsky
[not found] ` <b8b716a7-e235-38b2-ea6d-0a21881fa64e-5C7GfCeVMHo@public.gmane.org>
2019-11-27 0:41 ` Deng, Emily
2019-11-27 0:41 ` Deng, Emily
2019-12-02 19:24 ` Deng, Emily
2019-12-03 19:10 ` Andrey Grodzovsky
2019-12-03 19:44 ` Deucher, Alexander [this message]
2019-12-03 19:57 ` Andrey Grodzovsky
2019-12-03 19:59 ` Deucher, Alexander
2019-12-03 20:32 ` Andrey Grodzovsky
2019-12-03 20:58 ` Deng, Emily
2019-12-03 19:53 ` Deng, Emily
2020-02-05 18:24 ` Lucas Stach
2020-02-06 11:10 ` Lucas Stach
2020-02-06 11:49 ` Christian König
2020-02-06 14:49 ` Alex Deucher
2020-02-06 14:51 ` Christian König
2020-02-06 15:49 ` Andrey Grodzovsky
2020-02-10 16:55 ` Andrey Grodzovsky
2020-02-10 21:50 ` Luben Tuikov
2020-02-11 15:55 ` Andrey Grodzovsky
2020-02-11 21:27 ` Andrey Grodzovsky
2020-02-12 0:53 ` Luben Tuikov
2020-02-12 16:33 ` Andrey Grodzovsky
2020-07-21 11:03 ` Lucas Stach
2020-07-21 13:36 ` Andrey Grodzovsky
2020-07-21 13:39 ` Christian König
2020-07-21 13:42 ` Andrey Grodzovsky
2020-07-21 18:29 ` Luben Tuikov
2020-11-25 3:17 ` [PATCH 0/6] Allow to extend the timeout without jobs disappearing Luben Tuikov
2020-11-25 3:17 ` [PATCH 1/6] drm/scheduler: "node" --> "list" Luben Tuikov
2020-11-25 9:44 ` Christian König
2020-11-25 3:17 ` [PATCH 2/6] gpu/drm: ring_mirror_list --> pending_list Luben Tuikov
2020-11-25 9:47 ` Christian König
2020-11-25 16:42 ` Luben Tuikov
2020-11-25 3:17 ` [PATCH 3/6] drm/scheduler: Job timeout handler returns status Luben Tuikov
2020-11-25 4:41 ` kernel test robot
2020-11-25 9:50 ` Christian König
2020-11-25 16:48 ` Luben Tuikov
2020-11-25 11:04 ` Steven Price
2020-11-25 11:15 ` Lucas Stach
2020-11-25 11:22 ` Steven Price
2020-11-25 11:47 ` Lucas Stach
2020-11-25 12:41 ` Christian König
2020-11-26 15:06 ` Andrey Grodzovsky
2020-11-25 3:17 ` [PATCH 4/6] drm/scheduler: Essentialize the job done callback Luben Tuikov
2020-11-25 9:51 ` Christian König
2020-11-25 3:17 ` [PATCH 5/6] drm/amdgpu: Don't hardcode thread name length Luben Tuikov
2020-11-25 9:55 ` Christian König
2020-11-25 17:01 ` Luben Tuikov
2020-11-26 8:11 ` Christian König
2020-11-25 3:17 ` [PATCH 6/6] drm/sched: Make use of a "done" thread Luben Tuikov
2020-11-25 10:10 ` Christian König
2020-11-26 0:24 ` Luben Tuikov
2020-11-25 11:09 ` Steven Price
2020-11-26 0:30 ` Luben Tuikov
2020-02-07 15:26 ` [PATCH v4] drm/scheduler: Avoid accessing freed bad job Daniel Vetter
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