Unverified Commit 9d824c7f authored by Tvrtko Ursulin's avatar Tvrtko Ursulin Committed by Maíra Canal
Browse files

drm/v3d: Disable preemption while updating GPU stats 



We forgot to disable preemption around the write_seqcount_begin/end() pair
while updating GPU stats:

  [ ] WARNING: CPU: 2 PID: 12 at include/linux/seqlock.h:221 __seqprop_assert.isra.0+0x128/0x150 [v3d]
  [ ] Workqueue: v3d_bin drm_sched_run_job_work [gpu_sched]
 <...snip...>
  [ ] Call trace:
  [ ]  __seqprop_assert.isra.0+0x128/0x150 [v3d]
  [ ]  v3d_job_start_stats.isra.0+0x90/0x218 [v3d]
  [ ]  v3d_bin_job_run+0x23c/0x388 [v3d]
  [ ]  drm_sched_run_job_work+0x520/0x6d0 [gpu_sched]
  [ ]  process_one_work+0x62c/0xb48
  [ ]  worker_thread+0x468/0x5b0
  [ ]  kthread+0x1c4/0x1e0
  [ ]  ret_from_fork+0x10/0x20

Fix it.

Cc: Maíra Canal <mcanal@igalia.com>
Cc: stable@vger.kernel.org # v6.10+
Fixes: 6abe93b6 ("drm/v3d: Fix race-condition between sysfs/fdinfo and interrupt handler")
Signed-off-by: default avatarTvrtko Ursulin <tvrtko.ursulin@igalia.com>
Acked-by: default avatarMaíra Canal <mcanal@igalia.com>
Signed-off-by: default avatarMaíra Canal <mcanal@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240813102505.80512-1-tursulin@igalia.com
parent b49420d6

drivers/gpu/drm/v3d/v3d_sched.c

+6 −0
Original line number Diff line number Diff line
@@ -134,6 +134,8 @@ v3d_job_start_stats(struct v3d_job *job, enum v3d_queue queue) 
	struct v3d_stats *local_stats = &file->stats[queue];

	u64 now = local_clock();



	preempt_disable();



	write_seqcount_begin(&local_stats->lock);

	local_stats->start_ns = now;

	write_seqcount_end(&local_stats->lock);
@@ -141,6 +143,8 @@ v3d_job_start_stats(struct v3d_job *job, enum v3d_queue queue) 
	write_seqcount_begin(&global_stats->lock);

	global_stats->start_ns = now;

	write_seqcount_end(&global_stats->lock);



	preempt_enable();

}



static void
@@ -162,8 +166,10 @@ v3d_job_update_stats(struct v3d_job *job, enum v3d_queue queue) 
	struct v3d_stats *local_stats = &file->stats[queue];

	u64 now = local_clock();



	preempt_disable();

	v3d_stats_update(local_stats, now);

	v3d_stats_update(global_stats, now);

	preempt_enable();

}



static struct dma_fence *v3d_bin_job_run(struct drm_sched_job *sched_job)