Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Hi Lucas, Thank you for following up on this. Some things have slowed down, given the world pandemic we've been experiencing this year. I've had the design ready and half of it implemented and committed into a branch. Just as per what I wrote earlier this year on this thread. I need to finish the rest which isn't big, but does need some unravelling of the current code. Then I need testing, which I suppose a number of people can help, so long as they can make a frame time out and kick in the timeout handler. I'll have more details in a few weeks. Regards, Luben On 2020-07-21 9:42 a.m., Andrey Grodzovsky wrote: > Christian, I would want this very much but unfortunately I am on a strict > schedule for an internal project currently and hence will not be able to > actively participate. I will do my best to answer any questions Luben might > have > about current implementation. > > Andrey > > On 7/21/20 9:39 AM, Christian König wrote: >> Luben had a good idea how to tackle the whole job handling. >> >> Andrey/Lucas can you work with Luben to get this cleaned up because there >> are >> a lot of requirements on this which not only come from AMD. >> >> Thanks, >> Christian. >> >> Am 21.07.20 um 15:36 schrieb Andrey Grodzovsky: >>> Lucas, Luben picked the work on this a few month ago as I was diverted to a >>> different project. >>> >>> Luben, can you update Lucas please ? >>> >>> Andrey >>> >>> On 7/21/20 7:03 AM, Lucas Stach wrote: It seems we all dropped the ball on this one. I believe this is still an open issue. Has there been any progress from your side on fixing this? Regards, Lucas >> ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Christian, I would want this very much but unfortunately I am on a strict schedule for an internal project currently and hence will not be able to actively participate. I will do my best to answer any questions Luben might have about current implementation. Andrey On 7/21/20 9:39 AM, Christian König wrote: Luben had a good idea how to tackle the whole job handling. Andrey/Lucas can you work with Luben to get this cleaned up because there are a lot of requirements on this which not only come from AMD. Thanks, Christian. Am 21.07.20 um 15:36 schrieb Andrey Grodzovsky: Lucas, Luben picked the work on this a few month ago as I was diverted to a different project. Luben, can you update Lucas please ? Andrey On 7/21/20 7:03 AM, Lucas Stach wrote: It seems we all dropped the ball on this one. I believe this is still an open issue. Has there been any progress from your side on fixing this? Regards, Lucas ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Luben had a good idea how to tackle the whole job handling. Andrey/Lucas can you work with Luben to get this cleaned up because there are a lot of requirements on this which not only come from AMD. Thanks, Christian. Am 21.07.20 um 15:36 schrieb Andrey Grodzovsky: Lucas, Luben picked the work on this a few month ago as I was diverted to a different project. Luben, can you update Lucas please ? Andrey On 7/21/20 7:03 AM, Lucas Stach wrote: It seems we all dropped the ball on this one. I believe this is still an open issue. Has there been any progress from your side on fixing this? Regards, Lucas ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Lucas, Luben picked the work on this a few month ago as I was diverted to a different project. Luben, can you update Lucas please ? Andrey On 7/21/20 7:03 AM, Lucas Stach wrote: It seems we all dropped the ball on this one. I believe this is still an open issue. Has there been any progress from your side on fixing this? Regards, Lucas ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Hi Andrey, Am Mittwoch, den 12.02.2020, 11:33 -0500 schrieb Andrey Grodzovsky: > On 2/11/20 7:53 PM, Luben Tuikov wrote: > > On 2020-02-11 4:27 p.m., Andrey Grodzovsky wrote: > > > On 2/11/20 10:55 AM, Andrey Grodzovsky wrote: > > > > On 2/10/20 4:50 PM, Luben Tuikov wrote: > > > > > Hi Lucas, > > > > > > > > > > Thank you for bringing awareness of this issue, publicly. > > > > > > > > > > As soon as this patch showed up back in November of 2019, > > > > > I objected to it, privately. > > > > > > > > I didn't find this objection in my mail actually > > Yes, I didn't send it to you. > > > > > > > I suggested to instead use a _list_ to store the "state" of > > > > > all jobs of the same state. Then, at any time, timeout interrupt > > > > > or whatever, we can atomically (irq spinlock) move the timeout/bad > > > > > job to the timedout/cleanup/bad job list, and wake someone up > > > > > to deal with that list asynchronously, and return from the > > > > > interrupt/etc. > > > > > immediately. > > > > > > > > Sounds a good idea to me, i think enough for us to have 2 lists, > > > > timeout list for jobs scheduled to HW and not yet completed > > > > (completion fence signaled) and cleanup list for those that did > > > > complete. This should give alternative solution to the race condition > > > > this patch was addressing without causing the break the Lucas > > > > reported. If no one objects I think i can try implement it. > > > > > > > > Andrey > > > > > > Thinking more i realize Luben is right about having also bad job list as > > > this is needed for normal job competition (by fence callback from > > > amdgpu_fence_process) and you need to decide if you move it to cleanup > > > list from timeout list or not. If it's already in bad job list - meaning > > > that it's being processed by GPU recovery code you don't touch it, > > > otherwise you move it to cleanup list where it will be freed eventually > > > by invocation of drm_sched_get_cleanup_job. > > Yep... > > > > Perhaps fewer lists, than "timeout", "bad" and "cleanup" could be had. > > I'd also name the "bad" list as "recovery" list, as that is what would > > be done to commands on that list. > > > > "Timeout" is a status "timed-out", so perhaps just set the timeout > > flag and move it to a "done" list. (Note that the command can still > > complete asynchronously while on that list and while it has status > > "timed-out'.) > > > > The idea is that, > > 1) it avoid contention and races when more than one context > > can update the job at the same time, and > > 2) easy to process all jobs of a certain state and/or > > move them around, etc. > > > > Let's discuss it and come up with a plan. :-) > > > > Regards, > > Luben > > Sure, let me maybe come up with a draft patch so we have more concrete > stuff to discuss and review. It seems we all dropped the ball on this one. I believe this is still an open issue. Has there been any progress from your side on fixing this? Regards, Lucas ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On 2/11/20 7:53 PM, Luben Tuikov wrote: On 2020-02-11 4:27 p.m., Andrey Grodzovsky wrote: On 2/11/20 10:55 AM, Andrey Grodzovsky wrote: On 2/10/20 4:50 PM, Luben Tuikov wrote: Hi Lucas, Thank you for bringing awareness of this issue, publicly. As soon as this patch showed up back in November of 2019, I objected to it, privately. I didn't find this objection in my mail actually Yes, I didn't send it to you. I suggested to instead use a _list_ to store the "state" of all jobs of the same state. Then, at any time, timeout interrupt or whatever, we can atomically (irq spinlock) move the timeout/bad job to the timedout/cleanup/bad job list, and wake someone up to deal with that list asynchronously, and return from the interrupt/etc. immediately. Sounds a good idea to me, i think enough for us to have 2 lists, timeout list for jobs scheduled to HW and not yet completed (completion fence signaled) and cleanup list for those that did complete. This should give alternative solution to the race condition this patch was addressing without causing the break the Lucas reported. If no one objects I think i can try implement it. Andrey Thinking more i realize Luben is right about having also bad job list as this is needed for normal job competition (by fence callback from amdgpu_fence_process) and you need to decide if you move it to cleanup list from timeout list or not. If it's already in bad job list - meaning that it's being processed by GPU recovery code you don't touch it, otherwise you move it to cleanup list where it will be freed eventually by invocation of drm_sched_get_cleanup_job. Yep... Perhaps fewer lists, than "timeout", "bad" and "cleanup" could be had. I'd also name the "bad" list as "recovery" list, as that is what would be done to commands on that list. "Timeout" is a status "timed-out", so perhaps just set the timeout flag and move it to a "done" list. (Note that the command can still complete asynchronously while on that list and while it has status "timed-out'.) The idea is that, 1) it avoid contention and races when more than one context can update the job at the same time, and 2) easy to process all jobs of a certain state and/or move them around, etc. Let's discuss it and come up with a plan. :-) Regards, Luben Sure, let me maybe come up with a draft patch so we have more concrete stuff to discuss and review. Andrey Andrey Then in due time, if any more interrupts or whatnot take place, the job will either be in the timeout list or not. If it it, then the instigator backs off as someone else (the list handler) will/is awake and handling it (obviously a state variable may be kept as well). This draws somewhat from my days with iSCSI, SCSI and SAS, 15 years ago, where a device can complete a job (task) at anytime regardless of what the SCSI layer "thinks" the task's state is: timed-out, aborted, whatever. It is a very simple and elegant solution which generalizes well. Regards, Luben On 2020-02-10 11:55 a.m., Andrey Grodzovsky wrote: Lucas - Ping on my question and also I attached this temporary solution for etnaviv to clarify my point. If that something acceptable for now at least i can do the same for v3d where it requires a bit more code changes. Andrey On 2/6/20 10:49 AM, Andrey Grodzovsky wrote: Well a revert would break our driver. The real solution is that somebody needs to sit down, gather ALL the requirements and then come up with a solution which is clean and works for everyone. Christian. I can to take on this as indeed our general design on this becomes more and more entangled as GPU reset scenarios grow in complexity (at least in AMD driver). Currently I am on a high priority internal task which should take me around a week or 2 to finish and after that I can get to it. Regarding temporary solution - I looked into v3d and etnaviv use cases and we in AMD actually face the same scenario where we decide to skip HW reset if the guilty job did finish by the time we are processing the timeout (see amdgpu_device_gpu_recover and skip_hw_reset goto) - the difference is we always call drm_sched_stop/start irrespectively of whether we are going to actually HW reset or not (same as extend timeout). I wonder if something like this can be done also for ve3 and etnaviv ? Andrey ___ amd-gfx mailing list amd-...@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfxdata=02%7C01%7Candrey.grodzovsky%40amd.com%7Cef96617d23a54fe9b6ef08d7af0ac9db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637170333200621550sdata=wa7Eh3bdi%2BthYjjZF2yeTvTjNRipGPqVA%2FGQt0QL7R8%3Dreserved=0 ___ amd-gfx mailing list amd-...@lists.freedesktop.org
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On 2020-02-11 4:27 p.m., Andrey Grodzovsky wrote: > > On 2/11/20 10:55 AM, Andrey Grodzovsky wrote: >> On 2/10/20 4:50 PM, Luben Tuikov wrote: >>> Hi Lucas, >>> >>> Thank you for bringing awareness of this issue, publicly. >>> >>> As soon as this patch showed up back in November of 2019, >>> I objected to it, privately. >> >> >> I didn't find this objection in my mail actually Yes, I didn't send it to you. >>> I suggested to instead use a _list_ to store the "state" of >>> all jobs of the same state. Then, at any time, timeout interrupt >>> or whatever, we can atomically (irq spinlock) move the timeout/bad >>> job to the timedout/cleanup/bad job list, and wake someone up >>> to deal with that list asynchronously, and return from the >>> interrupt/etc. >>> immediately. >> >> >> Sounds a good idea to me, i think enough for us to have 2 lists, >> timeout list for jobs scheduled to HW and not yet completed >> (completion fence signaled) and cleanup list for those that did >> complete. This should give alternative solution to the race condition >> this patch was addressing without causing the break the Lucas >> reported. If no one objects I think i can try implement it. >> >> Andrey > > > Thinking more i realize Luben is right about having also bad job list as > this is needed for normal job competition (by fence callback from > amdgpu_fence_process) and you need to decide if you move it to cleanup > list from timeout list or not. If it's already in bad job list - meaning > that it's being processed by GPU recovery code you don't touch it, > otherwise you move it to cleanup list where it will be freed eventually > by invocation of drm_sched_get_cleanup_job. Yep... Perhaps fewer lists, than "timeout", "bad" and "cleanup" could be had. I'd also name the "bad" list as "recovery" list, as that is what would be done to commands on that list. "Timeout" is a status "timed-out", so perhaps just set the timeout flag and move it to a "done" list. (Note that the command can still complete asynchronously while on that list and while it has status "timed-out'.) The idea is that, 1) it avoid contention and races when more than one context can update the job at the same time, and 2) easy to process all jobs of a certain state and/or move them around, etc. Let's discuss it and come up with a plan. :-) Regards, Luben > > Andrey > > >> >> >>> >>> Then in due time, if any more interrupts or whatnot take place, >>> the job will either be in the timeout list or not. If it it, >>> then the instigator backs off as someone else (the list handler) will/is >>> awake and handling it (obviously a state variable may be kept as well). >>> >>> This draws somewhat from my days with iSCSI, SCSI and SAS, 15 years ago, >>> where a device can complete a job (task) at anytime regardless >>> of what the SCSI layer "thinks" the task's state is: timed-out, aborted, >>> whatever. It is a very simple and elegant solution which generalizes >>> well. >>> >>> Regards, >>> Luben >>> >>> On 2020-02-10 11:55 a.m., Andrey Grodzovsky wrote: Lucas - Ping on my question and also I attached this temporary solution for etnaviv to clarify my point. If that something acceptable for now at least i can do the same for v3d where it requires a bit more code changes. Andrey On 2/6/20 10:49 AM, Andrey Grodzovsky wrote: >> Well a revert would break our driver. >> >> The real solution is that somebody needs to sit down, gather ALL >> the requirements and then come up with a solution which is clean >> and works for everyone. >> >> Christian. > > I can to take on this as indeed our general design on this becomes > more and more entangled as GPU reset scenarios grow in complexity > (at least in AMD driver). Currently I am on a high priority > internal task which should take me around a week or 2 to finish and > after that I can get to it. > > Regarding temporary solution - I looked into v3d and etnaviv use > cases and we in AMD actually face the same scenario where we decide > to skip HW reset if the guilty job did finish by the time we are > processing the timeout (see amdgpu_device_gpu_recover and > skip_hw_reset goto) - the difference is we always call > drm_sched_stop/start irrespectively of whether we are going to > actually HW reset or not (same as extend timeout). I wonder if > something like this can be done also for ve3 and etnaviv ? > > Andrey ___ amd-gfx mailing list amd-...@lists.freedesktop.org
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On 2/11/20 10:55 AM, Andrey Grodzovsky wrote: On 2/10/20 4:50 PM, Luben Tuikov wrote: Hi Lucas, Thank you for bringing awareness of this issue, publicly. As soon as this patch showed up back in November of 2019, I objected to it, privately. I didn't find this objection in my mail actually I suggested to instead use a _list_ to store the "state" of all jobs of the same state. Then, at any time, timeout interrupt or whatever, we can atomically (irq spinlock) move the timeout/bad job to the timedout/cleanup/bad job list, and wake someone up to deal with that list asynchronously, and return from the interrupt/etc. immediately. Sounds a good idea to me, i think enough for us to have 2 lists, timeout list for jobs scheduled to HW and not yet completed (completion fence signaled) and cleanup list for those that did complete. This should give alternative solution to the race condition this patch was addressing without causing the break the Lucas reported. If no one objects I think i can try implement it. Andrey Thinking more i realize Luben is right about having also bad job list as this is needed for normal job competition (by fence callback from amdgpu_fence_process) and you need to decide if you move it to cleanup list from timeout list or not. If it's already in bad job list - meaning that it's being processed by GPU recovery code you don't touch it, otherwise you move it to cleanup list where it will be freed eventually by invocation of drm_sched_get_cleanup_job. Andrey Then in due time, if any more interrupts or whatnot take place, the job will either be in the timeout list or not. If it it, then the instigator backs off as someone else (the list handler) will/is awake and handling it (obviously a state variable may be kept as well). This draws somewhat from my days with iSCSI, SCSI and SAS, 15 years ago, where a device can complete a job (task) at anytime regardless of what the SCSI layer "thinks" the task's state is: timed-out, aborted, whatever. It is a very simple and elegant solution which generalizes well. Regards, Luben On 2020-02-10 11:55 a.m., Andrey Grodzovsky wrote: Lucas - Ping on my question and also I attached this temporary solution for etnaviv to clarify my point. If that something acceptable for now at least i can do the same for v3d where it requires a bit more code changes. Andrey On 2/6/20 10:49 AM, Andrey Grodzovsky wrote: Well a revert would break our driver. The real solution is that somebody needs to sit down, gather ALL the requirements and then come up with a solution which is clean and works for everyone. Christian. I can to take on this as indeed our general design on this becomes more and more entangled as GPU reset scenarios grow in complexity (at least in AMD driver). Currently I am on a high priority internal task which should take me around a week or 2 to finish and after that I can get to it. Regarding temporary solution - I looked into v3d and etnaviv use cases and we in AMD actually face the same scenario where we decide to skip HW reset if the guilty job did finish by the time we are processing the timeout (see amdgpu_device_gpu_recover and skip_hw_reset goto) - the difference is we always call drm_sched_stop/start irrespectively of whether we are going to actually HW reset or not (same as extend timeout). I wonder if something like this can be done also for ve3 and etnaviv ? Andrey ___ amd-gfx mailing list amd-...@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfxdata=02%7C01%7Candrey.grodzovsky%40amd.com%7Cef96617d23a54fe9b6ef08d7af0ac9db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637170333200621550sdata=wa7Eh3bdi%2BthYjjZF2yeTvTjNRipGPqVA%2FGQt0QL7R8%3Dreserved=0 ___ amd-gfx mailing list amd-...@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfxdata=02%7C01%7Candrey.grodzovsky%40amd.com%7Cef96617d23a54fe9b6ef08d7af0ac9db%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637170333200621550sdata=wa7Eh3bdi%2BthYjjZF2yeTvTjNRipGPqVA%2FGQt0QL7R8%3Dreserved=0 ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On 2/10/20 4:50 PM, Luben Tuikov wrote: Hi Lucas, Thank you for bringing awareness of this issue, publicly. As soon as this patch showed up back in November of 2019, I objected to it, privately. I didn't find this objection in my mail actually I suggested to instead use a _list_ to store the "state" of all jobs of the same state. Then, at any time, timeout interrupt or whatever, we can atomically (irq spinlock) move the timeout/bad job to the timedout/cleanup/bad job list, and wake someone up to deal with that list asynchronously, and return from the interrupt/etc. immediately. Sounds a good idea to me, i think enough for us to have 2 lists, timeout list for jobs scheduled to HW and not yet completed (completion fence signaled) and cleanup list for those that did complete. This should give alternative solution to the race condition this patch was addressing without causing the break the Lucas reported. If no one objects I think i can try implement it. Andrey Then in due time, if any more interrupts or whatnot take place, the job will either be in the timeout list or not. If it it, then the instigator backs off as someone else (the list handler) will/is awake and handling it (obviously a state variable may be kept as well). This draws somewhat from my days with iSCSI, SCSI and SAS, 15 years ago, where a device can complete a job (task) at anytime regardless of what the SCSI layer "thinks" the task's state is: timed-out, aborted, whatever. It is a very simple and elegant solution which generalizes well. Regards, Luben On 2020-02-10 11:55 a.m., Andrey Grodzovsky wrote: Lucas - Ping on my question and also I attached this temporary solution for etnaviv to clarify my point. If that something acceptable for now at least i can do the same for v3d where it requires a bit more code changes. Andrey On 2/6/20 10:49 AM, Andrey Grodzovsky wrote: Well a revert would break our driver. The real solution is that somebody needs to sit down, gather ALL the requirements and then come up with a solution which is clean and works for everyone. Christian. I can to take on this as indeed our general design on this becomes more and more entangled as GPU reset scenarios grow in complexity (at least in AMD driver). Currently I am on a high priority internal task which should take me around a week or 2 to finish and after that I can get to it. Regarding temporary solution - I looked into v3d and etnaviv use cases and we in AMD actually face the same scenario where we decide to skip HW reset if the guilty job did finish by the time we are processing the timeout (see amdgpu_device_gpu_recover and skip_hw_reset goto) - the difference is we always call drm_sched_stop/start irrespectively of whether we are going to actually HW reset or not (same as extend timeout). I wonder if something like this can be done also for ve3 and etnaviv ? Andrey ___ amd-gfx mailing list amd-...@lists.freedesktop.org https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfxdata=02%7C01%7Cluben.tuikov%40amd.com%7Cce97bc29988e4068ef8108d7ae4a043d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637169505277381327sdata=FyV0q3y5uWPwBgJF5QZLWARcXau916EUcYez2VA%2FqRA%3Dreserved=0 ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Hi Lucas, Thank you for bringing awareness of this issue, publicly. As soon as this patch showed up back in November of 2019, I objected to it, privately. I suggested to instead use a _list_ to store the "state" of all jobs of the same state. Then, at any time, timeout interrupt or whatever, we can atomically (irq spinlock) move the timeout/bad job to the timedout/cleanup/bad job list, and wake someone up to deal with that list asynchronously, and return from the interrupt/etc. immediately. Then in due time, if any more interrupts or whatnot take place, the job will either be in the timeout list or not. If it it, then the instigator backs off as someone else (the list handler) will/is awake and handling it (obviously a state variable may be kept as well). This draws somewhat from my days with iSCSI, SCSI and SAS, 15 years ago, where a device can complete a job (task) at anytime regardless of what the SCSI layer "thinks" the task's state is: timed-out, aborted, whatever. It is a very simple and elegant solution which generalizes well. Regards, Luben On 2020-02-10 11:55 a.m., Andrey Grodzovsky wrote: > Lucas - Ping on my question and also I attached this temporary solution for > etnaviv to clarify my point. If that something acceptable for now at least i > can do the same for v3d where it requires a bit more code changes. > > Andrey > > On 2/6/20 10:49 AM, Andrey Grodzovsky wrote: >>> Well a revert would break our driver. >>> >>> The real solution is that somebody needs to sit down, gather ALL the >>> requirements and then come up with a solution which is clean and works for >>> everyone. >>> >>> Christian. >> >> >> I can to take on this as indeed our general design on this becomes more and >> more entangled as GPU reset scenarios grow in complexity (at least in AMD >> driver). Currently I am on a high priority internal task which should take >> me around a week or 2 to finish and after that I can get to it. >> >> Regarding temporary solution - I looked into v3d and etnaviv use cases and >> we in AMD actually face the same scenario where we decide to skip HW reset >> if the guilty job did finish by the time we are processing the timeout (see >> amdgpu_device_gpu_recover and skip_hw_reset goto) - the difference is we >> always call drm_sched_stop/start irrespectively of whether we are going to >> actually HW reset or not (same as extend timeout). I wonder if something >> like this can be done also for ve3 and etnaviv ? >> >> Andrey > > ___ > amd-gfx mailing list > amd-...@lists.freedesktop.org > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfxdata=02%7C01%7Cluben.tuikov%40amd.com%7Cce97bc29988e4068ef8108d7ae4a043d%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637169505277381327sdata=FyV0q3y5uWPwBgJF5QZLWARcXau916EUcYez2VA%2FqRA%3Dreserved=0 > ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Lucas - Ping on my question and also I attached this temporary solution
for etnaviv to clarify my point. If that something acceptable for now at
least i can do the same for v3d where it requires a bit more code changes.
Andrey
On 2/6/20 10:49 AM, Andrey Grodzovsky wrote:
Well a revert would break our driver.
The real solution is that somebody needs to sit down, gather ALL the
requirements and then come up with a solution which is clean and
works for everyone.
Christian.
I can to take on this as indeed our general design on this becomes
more and more entangled as GPU reset scenarios grow in complexity (at
least in AMD driver). Currently I am on a high priority internal task
which should take me around a week or 2 to finish and after that I can
get to it.
Regarding temporary solution - I looked into v3d and etnaviv use
cases and we in AMD actually face the same scenario where we decide to
skip HW reset if the guilty job did finish by the time we are
processing the timeout (see amdgpu_device_gpu_recover and
skip_hw_reset goto) - the difference is we always call
drm_sched_stop/start irrespectively of whether we are going to
actually HW reset or not (same as extend timeout). I wonder if
something like this can be done also for ve3 and etnaviv ?
Andrey
>From c3fa87856608463f14dddb03346c31054f3137c9 Mon Sep 17 00:00:00 2001
From: Andrey Grodzovsky
Date: Mon, 10 Feb 2020 11:44:39 -0500
Subject: drm/etnaviv: Always execute sched stop and start.
During job timeout always stop and restart the scheduler even
if no HW resetis taking place.
Signed-off-by: Andrey Grodzovsky
---
drivers/gpu/drm/etnaviv/etnaviv_sched.c | 15 ++-
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_sched.c b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
index 4e3e95d..270caa8 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_sched.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_sched.c
@@ -89,12 +89,17 @@ static void etnaviv_sched_timedout_job(struct drm_sched_job *sched_job)
u32 dma_addr;
int change;
+
+
+ /* block scheduler */
+ drm_sched_stop(>sched, sched_job);
+
/*
* If the GPU managed to complete this jobs fence, the timout is
* spurious. Bail out.
*/
if (dma_fence_is_signaled(submit->out_fence))
- return;
+ goto skip_hw_reset;
/*
* If the GPU is still making forward progress on the front-end (which
@@ -105,12 +110,9 @@ static void etnaviv_sched_timedout_job(struct drm_sched_job *sched_job)
change = dma_addr - gpu->hangcheck_dma_addr;
if (change < 0 || change > 16) {
gpu->hangcheck_dma_addr = dma_addr;
- return;
+ goto skip_hw_reset;
}
- /* block scheduler */
- drm_sched_stop(>sched, sched_job);
-
if(sched_job)
drm_sched_increase_karma(sched_job);
@@ -120,6 +122,9 @@ static void etnaviv_sched_timedout_job(struct drm_sched_job *sched_job)
drm_sched_resubmit_jobs(>sched);
+
+skip_hw_reset:
+
/* restart scheduler after GPU is usable again */
drm_sched_start(>sched, true);
}
--
2.7.4
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On Thu, Feb 6, 2020 at 3:51 PM Christian König wrote:
>
> Am 06.02.20 um 15:49 schrieb Alex Deucher:
> > On Thu, Feb 6, 2020 at 6:50 AM Christian König
> > wrote:
> >> Am 06.02.20 um 12:10 schrieb Lucas Stach:
> >>> Hi all,
> >>>
> >>> On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
> Hi Andrey,
>
> This commit breaks all drivers, which may bail out of the timeout
> processing as they wish to extend the timeout (etnaviv, v3d).
>
> Those drivers currently just return from the timeout handler before
> calling drm_sched_stop(), which means with this commit applied we are
> removing the first job from the ring_mirror_list, but never put it
> back. This leads to jobs getting lost from the ring mirror, which then
> causes quite a bit of fallout like unsignaled fences.
>
> Not sure yet what to do about it, we can either add a function to add
> the job back to the ring_mirror if the driver wants to extend the
> timeout, or we could look for another way to stop
> drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
> processing.
> >>> So after thinking about this a bit more my opinion is that we need to
> >>> revert this change for now and go back to the drawing board for the
> >>> scheduler timeout handling.
> >>>
> >>> Right now this starts to feel like a big midlayer mistake with all the
> >>> very intricate intertwining between the drivers and the scheduler. The
> >>> rules on when it's safe to manipulate the ring mirror and when
> >>> completed jobs are signaled and freed are not really well specified.
> >>> The fact that we need to mutate state in order to get rid of races
> >>> instead of having a single big "timeout processing is owner of the
> >>> scheduler state for now" is a big fat warning sign IMHO.
> >> Yes, that strongly feels like a hack to me as well. But I didn't had
> >> time and still haven't to take a closer look and suggest something better.
> >>
> > In that case, can someone send me a revert?
>
> Well a revert would break our driver.
>
> The real solution is that somebody needs to sit down, gather ALL the
> requirements and then come up with a solution which is clean and works
> for everyone.
Uh generally oldest regression wins. As much as it sucks, but if we
don't do that then there's just too much room for arguing and maybe it
gets fixed in the next big rework ...
-Daniel
>
> Christian.
>
> >
> > Alex
> >
> >
> >> Christian.
> >>
> >>> It took me far longer than I'd like to admit to understand the failure
> >>> mode with fences not getting signaled after a GPU hang. The back and
> >>> forth between scheduler and driver code makes things really hard to
> >>> follow.
> >>>
> >>> Regards,
> >>> Lucas
> >>>
> Regards,
> Lucas
>
> On Mo, 2019-11-25 at 15:51 -0500, 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
> > Reviewed-by: Christian König
> > Tested-by: Emily Deng
> > ---
> >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(>job_list_lock, flags);
> > job = list_first_entry_or_null(>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
>
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On 2/6/20 9:51 AM, Christian König wrote:
Am 06.02.20 um 15:49 schrieb Alex Deucher:
On Thu, Feb 6, 2020 at 6:50 AM Christian König
wrote:
Am 06.02.20 um 12:10 schrieb Lucas Stach:
Hi all,
On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
Hi Andrey,
This commit breaks all drivers, which may bail out of the timeout
processing as they wish to extend the timeout (etnaviv, v3d).
Those drivers currently just return from the timeout handler before
calling drm_sched_stop(), which means with this commit applied we are
removing the first job from the ring_mirror_list, but never put it
back. This leads to jobs getting lost from the ring mirror, which
then
causes quite a bit of fallout like unsignaled fences.
Not sure yet what to do about it, we can either add a function to add
the job back to the ring_mirror if the driver wants to extend the
timeout, or we could look for another way to stop
drm_sched_cleanup_jobs from freeing jobs that are currently in
timeout
processing.
So after thinking about this a bit more my opinion is that we need to
revert this change for now and go back to the drawing board for the
scheduler timeout handling.
Right now this starts to feel like a big midlayer mistake with all the
very intricate intertwining between the drivers and the scheduler. The
rules on when it's safe to manipulate the ring mirror and when
completed jobs are signaled and freed are not really well specified.
The fact that we need to mutate state in order to get rid of races
instead of having a single big "timeout processing is owner of the
scheduler state for now" is a big fat warning sign IMHO.
Yes, that strongly feels like a hack to me as well. But I didn't had
time and still haven't to take a closer look and suggest something
better.
In that case, can someone send me a revert?
Well a revert would break our driver.
The real solution is that somebody needs to sit down, gather ALL the
requirements and then come up with a solution which is clean and works
for everyone.
Christian.
I can to take on this as indeed our general design on this becomes more
and more entangled as GPU reset scenarios grow in complexity (at least
in AMD driver). Currently I am on a high priority internal task which
should take me around a week or 2 to finish and after that I can get to it.
Regarding temporary solution - I looked into v3d and etnaviv use cases
and we in AMD actually face the same scenario where we decide to skip HW
reset if the guilty job did finish by the time we are processing the
timeout (see amdgpu_device_gpu_recover and skip_hw_reset goto) - the
difference is we always call drm_sched_stop/start irrespectively of
whether we are going to actually HW reset or not (same as extend
timeout). I wonder if something like this can be done also for ve3 and
etnaviv ?
Andrey
Alex
Christian.
It took me far longer than I'd like to admit to understand the failure
mode with fences not getting signaled after a GPU hang. The back and
forth between scheduler and driver code makes things really hard to
follow.
Regards,
Lucas
Regards,
Lucas
On Mo, 2019-11-25 at 15:51 -0500, 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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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.
+ */
+
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Am 06.02.20 um 15:49 schrieb Alex Deucher:
On Thu, Feb 6, 2020 at 6:50 AM Christian König
wrote:
Am 06.02.20 um 12:10 schrieb Lucas Stach:
Hi all,
On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
Hi Andrey,
This commit breaks all drivers, which may bail out of the timeout
processing as they wish to extend the timeout (etnaviv, v3d).
Those drivers currently just return from the timeout handler before
calling drm_sched_stop(), which means with this commit applied we are
removing the first job from the ring_mirror_list, but never put it
back. This leads to jobs getting lost from the ring mirror, which then
causes quite a bit of fallout like unsignaled fences.
Not sure yet what to do about it, we can either add a function to add
the job back to the ring_mirror if the driver wants to extend the
timeout, or we could look for another way to stop
drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
processing.
So after thinking about this a bit more my opinion is that we need to
revert this change for now and go back to the drawing board for the
scheduler timeout handling.
Right now this starts to feel like a big midlayer mistake with all the
very intricate intertwining between the drivers and the scheduler. The
rules on when it's safe to manipulate the ring mirror and when
completed jobs are signaled and freed are not really well specified.
The fact that we need to mutate state in order to get rid of races
instead of having a single big "timeout processing is owner of the
scheduler state for now" is a big fat warning sign IMHO.
Yes, that strongly feels like a hack to me as well. But I didn't had
time and still haven't to take a closer look and suggest something better.
In that case, can someone send me a revert?
Well a revert would break our driver.
The real solution is that somebody needs to sit down, gather ALL the
requirements and then come up with a solution which is clean and works
for everyone.
Christian.
Alex
Christian.
It took me far longer than I'd like to admit to understand the failure
mode with fences not getting signaled after a GPU hang. The back and
forth between scheduler and driver code makes things really hard to
follow.
Regards,
Lucas
Regards,
Lucas
On Mo, 2019-11-25 at 15:51 -0500, 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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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(>node);
+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
}
spin_lock_irqsave(>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
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
On Thu, Feb 6, 2020 at 6:50 AM Christian König
wrote:
>
> Am 06.02.20 um 12:10 schrieb Lucas Stach:
> > Hi all,
> >
> > On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
> >> Hi Andrey,
> >>
> >> This commit breaks all drivers, which may bail out of the timeout
> >> processing as they wish to extend the timeout (etnaviv, v3d).
> >>
> >> Those drivers currently just return from the timeout handler before
> >> calling drm_sched_stop(), which means with this commit applied we are
> >> removing the first job from the ring_mirror_list, but never put it
> >> back. This leads to jobs getting lost from the ring mirror, which then
> >> causes quite a bit of fallout like unsignaled fences.
> >>
> >> Not sure yet what to do about it, we can either add a function to add
> >> the job back to the ring_mirror if the driver wants to extend the
> >> timeout, or we could look for another way to stop
> >> drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
> >> processing.
> > So after thinking about this a bit more my opinion is that we need to
> > revert this change for now and go back to the drawing board for the
> > scheduler timeout handling.
> >
> > Right now this starts to feel like a big midlayer mistake with all the
> > very intricate intertwining between the drivers and the scheduler. The
> > rules on when it's safe to manipulate the ring mirror and when
> > completed jobs are signaled and freed are not really well specified.
> > The fact that we need to mutate state in order to get rid of races
> > instead of having a single big "timeout processing is owner of the
> > scheduler state for now" is a big fat warning sign IMHO.
>
> Yes, that strongly feels like a hack to me as well. But I didn't had
> time and still haven't to take a closer look and suggest something better.
>
In that case, can someone send me a revert?
Alex
> Christian.
>
> >
> > It took me far longer than I'd like to admit to understand the failure
> > mode with fences not getting signaled after a GPU hang. The back and
> > forth between scheduler and driver code makes things really hard to
> > follow.
> >
> > Regards,
> > Lucas
> >
> >> Regards,
> >> Lucas
> >>
> >> On Mo, 2019-11-25 at 15:51 -0500, 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
> >>> Reviewed-by: Christian König
> >>> Tested-by: Emily Deng
> >>> ---
> >>> 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(>job_list_lock, flags);
> >>> job = list_first_entry_or_null(>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(>node);
> >>> + spin_unlock_irqrestore(>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(>job_list_lock, flags);
> >>> }
> >>>
> >>> spin_lock_irqsave(>job_list_lock, flags);
> >>> @@ -370,6 +383,20 @@ void drm_sched_stop(struct drm_gpu_scheduler *sched,
> >>> struct
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Am 06.02.20 um 12:10 schrieb Lucas Stach:
Hi all,
On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
Hi Andrey,
This commit breaks all drivers, which may bail out of the timeout
processing as they wish to extend the timeout (etnaviv, v3d).
Those drivers currently just return from the timeout handler before
calling drm_sched_stop(), which means with this commit applied we are
removing the first job from the ring_mirror_list, but never put it
back. This leads to jobs getting lost from the ring mirror, which then
causes quite a bit of fallout like unsignaled fences.
Not sure yet what to do about it, we can either add a function to add
the job back to the ring_mirror if the driver wants to extend the
timeout, or we could look for another way to stop
drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
processing.
So after thinking about this a bit more my opinion is that we need to
revert this change for now and go back to the drawing board for the
scheduler timeout handling.
Right now this starts to feel like a big midlayer mistake with all the
very intricate intertwining between the drivers and the scheduler. The
rules on when it's safe to manipulate the ring mirror and when
completed jobs are signaled and freed are not really well specified.
The fact that we need to mutate state in order to get rid of races
instead of having a single big "timeout processing is owner of the
scheduler state for now" is a big fat warning sign IMHO.
Yes, that strongly feels like a hack to me as well. But I didn't had
time and still haven't to take a closer look and suggest something better.
Christian.
It took me far longer than I'd like to admit to understand the failure
mode with fences not getting signaled after a GPU hang. The back and
forth between scheduler and driver code makes things really hard to
follow.
Regards,
Lucas
Regards,
Lucas
On Mo, 2019-11-25 at 15:51 -0500, 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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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(>node);
+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
}
spin_lock_irqsave(>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.
+*/
+
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Hi all,
On Mi, 2020-02-05 at 19:24 +0100, Lucas Stach wrote:
> Hi Andrey,
>
> This commit breaks all drivers, which may bail out of the timeout
> processing as they wish to extend the timeout (etnaviv, v3d).
>
> Those drivers currently just return from the timeout handler before
> calling drm_sched_stop(), which means with this commit applied we are
> removing the first job from the ring_mirror_list, but never put it
> back. This leads to jobs getting lost from the ring mirror, which then
> causes quite a bit of fallout like unsignaled fences.
>
> Not sure yet what to do about it, we can either add a function to add
> the job back to the ring_mirror if the driver wants to extend the
> timeout, or we could look for another way to stop
> drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
> processing.
So after thinking about this a bit more my opinion is that we need to
revert this change for now and go back to the drawing board for the
scheduler timeout handling.
Right now this starts to feel like a big midlayer mistake with all the
very intricate intertwining between the drivers and the scheduler. The
rules on when it's safe to manipulate the ring mirror and when
completed jobs are signaled and freed are not really well specified.
The fact that we need to mutate state in order to get rid of races
instead of having a single big "timeout processing is owner of the
scheduler state for now" is a big fat warning sign IMHO.
It took me far longer than I'd like to admit to understand the failure
mode with fences not getting signaled after a GPU hang. The back and
forth between scheduler and driver code makes things really hard to
follow.
Regards,
Lucas
> Regards,
> Lucas
>
> On Mo, 2019-11-25 at 15:51 -0500, 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
> > Reviewed-by: Christian König
> > Tested-by: Emily Deng
> > ---
> > 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(>job_list_lock, flags);
> > job = list_first_entry_or_null(>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(>node);
> > + spin_unlock_irqrestore(>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(>job_list_lock, flags);
> > }
> >
> > spin_lock_irqsave(>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
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Hi Andrey,
This commit breaks all drivers, which may bail out of the timeout
processing as they wish to extend the timeout (etnaviv, v3d).
Those drivers currently just return from the timeout handler before
calling drm_sched_stop(), which means with this commit applied we are
removing the first job from the ring_mirror_list, but never put it
back. This leads to jobs getting lost from the ring mirror, which then
causes quite a bit of fallout like unsignaled fences.
Not sure yet what to do about it, we can either add a function to add
the job back to the ring_mirror if the driver wants to extend the
timeout, or we could look for another way to stop
drm_sched_cleanup_jobs from freeing jobs that are currently in timeout
processing.
Regards,
Lucas
On Mo, 2019-11-25 at 15:51 -0500, 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
> Reviewed-by: Christian König
> Tested-by: Emily Deng
> ---
> 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(>job_list_lock, flags);
> job = list_first_entry_or_null(>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(>node);
> + spin_unlock_irqrestore(>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(>job_list_lock, flags);
> }
>
> spin_lock_irqsave(>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(>node, >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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dri-devel@lists.freedesktop.org
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RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only] Hi Andrey, Thanks very much. Best wishes Emily Deng From: Grodzovsky, Andrey Sent: Tuesday, December 3, 2019 12:33 PM To: Deucher, Alexander ; Deng, Emily Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig, Christian ; steven.pr...@arm.com Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. Turns out Steven's patch was already in so i just cherry-picked the change from drm-next-misc Emily - it's in. Andrey On 12/3/19 2:59 PM, Deucher, Alexander wrote: [AMD Official Use Only - Internal Distribution Only] Cherry pick whatever dependencies you need or pick the older version of the patch. Either way works. Alex From: Grodzovsky, Andrey <mailto:andrey.grodzov...@amd.com> Sent: Tuesday, December 3, 2019 2:57 PM To: Deucher, Alexander <mailto:alexander.deuc...@amd.com>; Deng, Emily <mailto:emily.d...@amd.com> Cc: dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org> <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org> <mailto:amd-...@lists.freedesktop.org>; Koenig, Christian <mailto:christian.koe...@amd.com>; steven.pr...@arm.com<mailto:steven.pr...@arm.com> <mailto:steven.pr...@arm.com> Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. I don't think i can apply this patch 'as is' as this has dependency on patch by Steven which also wasn't applied yet - 588b982 Steven Price6 weeks ago drm: Don't free jobs in wait_event_interruptible() Andrey On 12/3/19 2:44 PM, Deucher, Alexander wrote: [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 <mailto:andrey.grodzov...@amd.com> Sent: Tuesday, December 3, 2019 2:10 PM To: Deng, Emily <mailto:emily.d...@amd.com>; Deucher, Alexander <mailto:alexander.deuc...@amd.com> Cc: dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org> <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org> <mailto:amd-...@lists.freedesktop.org>; Koenig, Christian <mailto:christian.koe...@amd.com>; steven.pr...@arm.com<mailto:steven.pr...@arm.com> <mailto:steven.pr...@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 >> <mailto:andrey.grodzov...@amd.com> >> Cc: dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org>; >> amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org>; Koenig, >> Christian <mailto:christian.koe...@amd.com>; >> steven.pr...@arm.com<mailto:steven.pr...@arm.com> >> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. >> >> [AMD Official Use Only - Internal Distribution Only] >> >> Reviewed-by: Emily Deng <mailto:emily.d...@amd.com> >> >>> -Original Message- >>> From: Grodzovsky, Andrey >>> <mailto:andrey.grodzov...@amd.com> >>> Sent: Tuesday, November 26, 2019 7:37 AM >>> Cc: >>> dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org>; >>> amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org>; >>> Koenig, Christian >>> <mailto:christian.koe...@amd.com>; Deng, Emily >>> <mailto:emily.d...@amd.com>; >>> steven.pr...@arm.com<mailto:steven.pr...@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
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Turns out Steven's patch was already in so i just cherry-picked the change from drm-next-misc Emily - it's in. Andrey On 12/3/19 2:59 PM, Deucher, Alexander wrote: [AMD Official Use Only - Internal Distribution Only] Cherry pick whatever dependencies you need or pick the older version of the patch. Either way works. Alex *From:* Grodzovsky, Andrey *Sent:* Tuesday, December 3, 2019 2:57 PM *To:* Deucher, Alexander ; Deng, Emily *Cc:* dri-devel@lists.freedesktop.org ; amd-...@lists.freedesktop.org ; Koenig, Christian ; steven.pr...@arm.com *Subject:* Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. I don't think i can apply this patch 'as is' as this has dependency on patch by Steven which also wasn't applied yet - 588b982 Steven Price 6 weeks ago drm: Don't free jobs in wait_event_interruptible() Andrey On 12/3/19 2:44 PM, Deucher, Alexander wrote: [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 <mailto:andrey.grodzov...@amd.com> *Sent:* Tuesday, December 3, 2019 2:10 PM *To:* Deng, Emily <mailto:emily.d...@amd.com>; Deucher, Alexander <mailto:alexander.deuc...@amd.com> *Cc:* dri-devel@lists.freedesktop.org <mailto:dri-devel@lists.freedesktop.org> <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org <mailto:amd-...@lists.freedesktop.org> <mailto:amd-...@lists.freedesktop.org>; Koenig, Christian <mailto:christian.koe...@amd.com>; steven.pr...@arm.com <mailto:steven.pr...@arm.com> <mailto:steven.pr...@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 <mailto:andrey.grodzov...@amd.com> >> Cc: dri-devel@lists.freedesktop.org <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org <mailto:amd-...@lists.freedesktop.org>; Koenig, >> Christian <mailto:christian.koe...@amd.com>; steven.pr...@arm.com <mailto:steven.pr...@arm.com> >> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. >> >> [AMD Official Use Only - Internal Distribution Only] >> >> Reviewed-by: Emily Deng <mailto:emily.d...@amd.com> >> >>> -Original Message- >>> From: Grodzovsky, Andrey <mailto:andrey.grodzov...@amd.com> >>> Sent: Tuesday, November 26, 2019 7:37 AM >>> Cc: dri-devel@lists.freedesktop.org <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org <mailto:amd-...@lists.freedesktop.org>; >>> Koenig, Christian <mailto:christian.koe...@amd.com>; Deng, Emily >>> <mailto:emily.d...@amd.com>; steven.pr...@arm.com <mailto:steven.pr...@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 <mailto:andrey.grodzov...@amd.com> >>>> Reviewed-by: Christian König <mailto:christian.koe...@amd.com> >>>> Tested-
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only] Cherry pick whatever dependencies you need or pick the older version of the patch. Either way works. Alex From: Grodzovsky, Andrey Sent: Tuesday, December 3, 2019 2:57 PM To: Deucher, Alexander ; Deng, Emily Cc: dri-devel@lists.freedesktop.org ; amd-...@lists.freedesktop.org ; Koenig, Christian ; steven.pr...@arm.com Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. I don't think i can apply this patch 'as is' as this has dependency on patch by Steven which also wasn't applied yet - 588b982 Steven Price6 weeks ago drm: Don't free jobs in wait_event_interruptible() Andrey On 12/3/19 2:44 PM, Deucher, Alexander wrote: [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 <mailto:andrey.grodzov...@amd.com> Sent: Tuesday, December 3, 2019 2:10 PM To: Deng, Emily <mailto:emily.d...@amd.com>; Deucher, Alexander <mailto:alexander.deuc...@amd.com> Cc: dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org> <mailto:dri-devel@lists.freedesktop.org>; amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org> <mailto:amd-...@lists.freedesktop.org>; Koenig, Christian <mailto:christian.koe...@amd.com>; steven.pr...@arm.com<mailto:steven.pr...@arm.com> <mailto:steven.pr...@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 >> <mailto:andrey.grodzov...@amd.com> >> Cc: dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org>; >> amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org>; Koenig, >> Christian <mailto:christian.koe...@amd.com>; >> steven.pr...@arm.com<mailto:steven.pr...@arm.com> >> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job. >> >> [AMD Official Use Only - Internal Distribution Only] >> >> Reviewed-by: Emily Deng <mailto:emily.d...@amd.com> >> >>> -Original Message- >>> From: Grodzovsky, Andrey >>> <mailto:andrey.grodzov...@amd.com> >>> Sent: Tuesday, November 26, 2019 7:37 AM >>> Cc: >>> dri-devel@lists.freedesktop.org<mailto:dri-devel@lists.freedesktop.org>; >>> amd-...@lists.freedesktop.org<mailto:amd-...@lists.freedesktop.org>; >>> Koenig, Christian >>> <mailto:christian.koe...@amd.com>; Deng, Emily >>> <mailto:emily.d...@amd.com>; >>> steven.pr...@arm.com<mailto:steven.pr...@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 >>>> <mailto:andrey.grodzov...@amd.com> >>>> Reviewed-by: Christian König >>>> <mailto:christian.koe...@amd.com> >>>> Tested-by: Emily Deng <mailto:emily.d...@amd.com> >>>> --- >>>>drivers/gpu/drm/scheduler/sched_main.c | 27 >>> +++ >>
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
I don't think i can apply this patch 'as is' as this has dependency on
patch by Steven which also wasn't applied yet - 588b982 Steven
Price 6 weeks ago drm: Don't free jobs in
wait_event_interruptible()
Andrey
On 12/3/19 2:44 PM, Deucher, Alexander wrote:
[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
*Sent:* Tuesday, December 3, 2019 2:10 PM
*To:* Deng, Emily ; Deucher, Alexander
*Cc:* dri-devel@lists.freedesktop.org
; amd-...@lists.freedesktop.org
; Koenig, Christian
; steven.pr...@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
>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
Koenig,
>> Christian ; steven.pr...@arm.com
>> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>>
>> [AMD Official Use Only - Internal Distribution Only]
>>
>> Reviewed-by: Emily Deng
>>
>>> -Original Message-
>>> From: Grodzovsky, Andrey
>>> Sent: Tuesday, November 26, 2019 7:37 AM
>>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
>>> Koenig, Christian ; Deng, Emily
>>> ; steven.pr...@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
>>>> Reviewed-by: Christian König
>>>> Tested-by: Emily Deng
>>>> ---
>>>> 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(>job_list_lock, flags);
>>>> job = list_first_entry_or_null(>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(>node);
>>>> + spin_unlock_irqrestore(>job_list_lock, flags);
>>>> +
>>>> job->sched->ops->timedout_job(job);
>>>>
>>>>
RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Hi Alex,
When we will cherry pick those patches to drm-next?
>-Original Message-
>From: Grodzovsky, Andrey
>Sent: Tuesday, December 3, 2019 11:10 AM
>To: Deng, Emily ; Deucher, Alexander
>
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; steven.pr...@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
>>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
>>> Koenig, Christian ; steven.pr...@arm.com
>>> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>>>
>>> [AMD Official Use Only - Internal Distribution Only]
>>>
>>> Reviewed-by: Emily Deng
>>>
>>>> -Original Message-
>>>> From: Grodzovsky, Andrey
>>>> Sent: Tuesday, November 26, 2019 7:37 AM
>>>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
>>>> Koenig, Christian ; Deng, Emily
>>>> ; steven.pr...@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
>>>>> Reviewed-by: Christian König
>>>>> Tested-by: Emily Deng
>>>>> ---
>>>>>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(>job_list_lock, flags);
>>>>> job = list_first_entry_or_null(>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(>node);
>>>>> + spin_unlock_irqrestore(>job_list_l
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[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
Sent: Tuesday, December 3, 2019 2:10 PM
To: Deng, Emily ; Deucher, Alexander
Cc: dri-devel@lists.freedesktop.org ;
amd-...@lists.freedesktop.org ; Koenig,
Christian ; steven.pr...@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
>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>> Christian ; steven.pr...@arm.com
>> Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>>
>> [AMD Official Use Only - Internal Distribution Only]
>>
>> Reviewed-by: Emily Deng
>>
>>> -Original Message-
>>> From: Grodzovsky, Andrey
>>> Sent: Tuesday, November 26, 2019 7:37 AM
>>> Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
>>> Koenig, Christian ; Deng, Emily
>>> ; steven.pr...@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
>>>> Reviewed-by: Christian König
>>>> Tested-by: Emily Deng
>>>> ---
>>>>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(>job_list_lock, flags);
>>>> job = list_first_entry_or_null(>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(>node);
>>>> + spin_unlock_irqrestore(>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;
>>
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
Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
Christian ; steven.pr...@arm.com
Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Reviewed-by: Emily Deng
-Original Message-
From: Grodzovsky, Andrey
Sent: Tuesday, November 26, 2019 7:37 AM
Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
Koenig, Christian ; Deng, Emily
; steven.pr...@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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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(>node);
+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
}
spin_lock_irqsave(>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(>node, >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.
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[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
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; steven.pr...@arm.com
>Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>
>[AMD Official Use Only - Internal Distribution Only]
>
>Reviewed-by: Emily Deng
>
>>-Original Message-
>>From: Grodzovsky, Andrey
>>Sent: Tuesday, November 26, 2019 7:37 AM
>>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org;
>>Koenig, Christian ; Deng, Emily
>>; steven.pr...@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
>>> Reviewed-by: Christian König
>>> Tested-by: Emily Deng
>>> ---
>>> 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(>job_list_lock, flags);
>>> job = list_first_entry_or_null(>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(>node);
>>> + spin_unlock_irqrestore(>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(>job_list_lock, flags);
>>> }
>>>
>>> spin_lock_irqsave(>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(>node, >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.
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Reviewed-by: Emily Deng
>-Original Message-
>From: Grodzovsky, Andrey
>Sent: Tuesday, November 26, 2019 7:37 AM
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; Deng, Emily
>; steven.pr...@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
>> Reviewed-by: Christian König
>> Tested-by: Emily Deng
>> ---
>> 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(>job_list_lock, flags);
>> job = list_first_entry_or_null(>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(>node);
>> +spin_unlock_irqrestore(>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(>job_list_lock, flags);
>> }
>>
>> spin_lock_irqsave(>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(>node, >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.
___
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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(>node);
+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
}
spin_lock_irqsave(>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(>node, >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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Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
I recently updated amd-staging-drm-next. Apply whatever makes sense for now
and it'll naturally fall out in the next rebase.
Alex
From: Grodzovsky, Andrey
Sent: Monday, November 25, 2019 7:09 PM
To: Deng, Emily
Cc: dri-devel@lists.freedesktop.org ;
amd-...@lists.freedesktop.org ; Koenig,
Christian ; steven.pr...@arm.com
; Deucher, Alexander
Subject: Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Christian asked to submit it to drm-misc instead of our drm-next to avoid later
conflicts with Steven's patch which he mentioned in this thread which is not in
drm-next yet.
Christian, Alex, once this merged to drm-misc I guess we need to pull all
latest changes from there to drm-next so the issue Emily reported can be
avoided.
Andrey
From: Deng, Emily
Sent: 25 November 2019 16:44:36
To: Grodzovsky, Andrey
Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
Christian; steven.pr...@arm.com; Grodzovsky, Andrey
Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Hi Andrey,
Seems you didn't submit this patch?
Best wishes
Emily Deng
>-Original Message-
>From: Andrey Grodzovsky
>Sent: Monday, November 25, 2019 12:51 PM
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; Deng, Emily
>; steven.pr...@arm.com; Grodzovsky, Andrey
>
>Subject: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>
>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
>Reviewed-by: Christian König
>Tested-by: Emily Deng
>---
> 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(>job_list_lock, flags);
> job = list_first_entry_or_null(>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(>node);
>+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
> }
>
> spin_lock_irqsave(>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.
>+ */
Re: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
Christian asked to submit it to drm-misc instead of our drm-next to avoid later
conflicts with Steven's patch which he mentioned in this thread which is not in
drm-next yet.
Christian, Alex, once this merged to drm-misc I guess we need to pull all
latest changes from there to drm-next so the issue Emily reported can be
avoided.
Andrey
From: Deng, Emily
Sent: 25 November 2019 16:44:36
To: Grodzovsky, Andrey
Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
Christian; steven.pr...@arm.com; Grodzovsky, Andrey
Subject: RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Hi Andrey,
Seems you didn't submit this patch?
Best wishes
Emily Deng
>-Original Message-
>From: Andrey Grodzovsky
>Sent: Monday, November 25, 2019 12:51 PM
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; Deng, Emily
>; steven.pr...@arm.com; Grodzovsky, Andrey
>
>Subject: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>
>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
>Reviewed-by: Christian König
>Tested-by: Emily Deng
>---
> 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(>job_list_lock, flags);
> job = list_first_entry_or_null(>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(>node);
>+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
> }
>
> spin_lock_irqsave(>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(>node, >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.
>--
>2.7.4
___
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RE: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
[AMD Official Use Only - Internal Distribution Only]
Hi Andrey,
Seems you didn't submit this patch?
Best wishes
Emily Deng
>-Original Message-
>From: Andrey Grodzovsky
>Sent: Monday, November 25, 2019 12:51 PM
>Cc: dri-devel@lists.freedesktop.org; amd-...@lists.freedesktop.org; Koenig,
>Christian ; Deng, Emily
>; steven.pr...@arm.com; Grodzovsky, Andrey
>
>Subject: [PATCH v4] drm/scheduler: Avoid accessing freed bad job.
>
>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
>Reviewed-by: Christian König
>Tested-by: Emily Deng
>---
> 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(>job_list_lock, flags);
> job = list_first_entry_or_null(>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(>node);
>+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
> }
>
> spin_lock_irqsave(>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(>node, >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.
>--
>2.7.4
___
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[PATCH v4] drm/scheduler: Avoid accessing freed bad job.
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
Reviewed-by: Christian König
Tested-by: Emily Deng
---
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(>job_list_lock, flags);
job = list_first_entry_or_null(>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(>node);
+ spin_unlock_irqrestore(>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(>job_list_lock, flags);
}
spin_lock_irqsave(>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(>node, >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.
--
2.7.4
___
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