diff options
| author | Steven Price <steven.price@arm.com> | 2019-10-09 10:44:55 +0100 |
|---|---|---|
| committer | Rob Herring <robh@kernel.org> | 2019-10-15 11:38:22 -0500 |
| commit | 5b3ec8134f5f9fa1ed0a538441a495521078bbee (patch) | |
| tree | f6ef968ec57b77e4c8f44d388b4cc427a1ae347b | |
| parent | eda6d764ac33d9ce8d656fa381f05b3feae09085 (diff) | |
| download | linux-5b3ec8134f5f9fa1ed0a538441a495521078bbee.tar.bz2 | |
drm/panfrost: Handle resetting on timeout better
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.
Fixes: aa20236784ab ("drm/panfrost: Prevent concurrent resets")
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191009094456.9704-1-steven.price@arm.com
| -rw-r--r-- | drivers/gpu/drm/panfrost/panfrost_job.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c index a58551668d9a..21f34d44aac2 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); spin_lock_irqsave(&pfdev->js->job_lock, flags); for (i = 0; i < NUM_JOB_SLOTS; i++) { |