6.10-stable review patch. If anyone has any objections, please let me know.
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From: Tvrtko Ursulin tvrtko.ursulin@igalia.com
commit 9d824c7fce58f59982228aa85b0376b113cdfa35 upstream.
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: 6abe93b621ab ("drm/v3d: Fix race-condition between sysfs/fdinfo and interrupt handler") Signed-off-by: Tvrtko Ursulin tvrtko.ursulin@igalia.com Acked-by: Maíra Canal mcanal@igalia.com Signed-off-by: Maíra Canal mcanal@igalia.com Link: https://patchwork.freedesktop.org/patch/msgid/20240813102505.80512-1-tursuli... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/v3d/v3d_sched.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c index b8682818bafa..ad1e6236ff6f 100644 --- a/drivers/gpu/drm/v3d/v3d_sched.c +++ b/drivers/gpu/drm/v3d/v3d_sched.c @@ -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)