On 07/10/2019 17:14, Tomeu Vizoso wrote: > On 10/7/19 6:09 AM, Neil Armstrong wrote: >> Hi Steven, >> >> On 07/10/2019 14:50, Steven Price wrote: >>> Panfrost uses multiple schedulers (one for each slot, so 2 in reality), >>> and on a timeout has to stop all the schedulers to safely perform a >>> reset. However more than one scheduler can trigger a timeout at the same >>> time. This race condition results in jobs being freed while they are >>> still in use. >>> >>> When stopping other slots use cancel_delayed_work_sync() to ensure that >>> any timeout started for that slot has completed. Also use >>> mutex_trylock() to obtain reset_lock. This means that only one thread >>> attempts the reset, the other threads will simply complete without doing >>> anything (the first thread will wait for this in the call to >>> cancel_delayed_work_sync()). >>> >>> While we're here and since the function is already dependent on >>> sched_job not being NULL, let's remove the unnecessary checks, along >>> with a commented out call to panfrost_core_dump() which has never >>> existed in mainline. >>> >> >> A Fixes: tags would be welcome here so it would be backported to v5.3 >> >>> Signed-off-by: Steven Price <steven.price@xxxxxxx> >>> --- >>> This is a tidied up version of the patch orginally posted here: >>> http://lkml.kernel.org/r/26ae2a4d-8df1-e8db-3060-41638ed63e2a%40arm.com >>> >>> drivers/gpu/drm/panfrost/panfrost_job.c | 17 +++++++++++------ >>> 1 file changed, 11 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c >>> b/drivers/gpu/drm/panfrost/panfrost_job.c >>> index a58551668d9a..dcc9a7603685 100644 >>> --- a/drivers/gpu/drm/panfrost/panfrost_job.c >>> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c >>> @@ -381,13 +381,19 @@ static void panfrost_job_timedout(struct >>> drm_sched_job *sched_job) >>> job_read(pfdev, JS_TAIL_LO(js)), >>> sched_job); >>> - mutex_lock(&pfdev->reset_lock); >>> + if (!mutex_trylock(&pfdev->reset_lock)) >>> + return; >>> - for (i = 0; i < NUM_JOB_SLOTS; i++) >>> - drm_sched_stop(&pfdev->js->queue[i].sched, sched_job); >>> + for (i = 0; i < NUM_JOB_SLOTS; i++) { >>> + struct drm_gpu_scheduler *sched = &pfdev->js->queue[i].sched; >>> + >>> + drm_sched_stop(sched, sched_job); >>> + if (js != i) >>> + /* Ensure any timeouts on other slots have finished */ >>> + cancel_delayed_work_sync(&sched->work_tdr); >>> + } >>> - if (sched_job) >>> - drm_sched_increase_karma(sched_job); >>> + drm_sched_increase_karma(sched_job); >> >> Indeed looks cleaner. >> >>> spin_lock_irqsave(&pfdev->js->job_lock, flags); >>> for (i = 0; i < NUM_JOB_SLOTS; i++) { >>> @@ -398,7 +404,6 @@ static void panfrost_job_timedout(struct >>> drm_sched_job *sched_job) >>> } >>> spin_unlock_irqrestore(&pfdev->js->job_lock, flags); >>> - /* panfrost_core_dump(pfdev); */ >> >> This should be cleaned in another patch ! > > Seems to me that this should be some kind of TODO, see > etnaviv_core_dump() for the kind of things we could be doing. > > Maybe we can delete this line and mention this in the TODO file? Fair enough - I'll split this into a separate patch and add an entry to the TODO file. kbase has a mechanism to "dump on job fault" [1],[2] so we could do something similar. Steve [1] https://gitlab.freedesktop.org/panfrost/mali_kbase/blob/master/driver/product/kernel/drivers/gpu/arm/midgard/backend/gpu/mali_kbase_debug_job_fault_backend.c [2] https://gitlab.freedesktop.org/panfrost/mali_kbase/blob/master/driver/product/kernel/drivers/gpu/arm/midgard/mali_kbase_debug_job_fault.c > Cheers, > > Tomeu > >>> panfrost_devfreq_record_transition(pfdev, js); >>> panfrost_device_reset(pfdev); >>> >> >> Thanks, >> Testing it right now with the last change removed (doesn't apply on >> v5.3 with it), >> results in a few hours... or minutes ! >> >> >> Neil >> > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel