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media: cedrus: Fix watchdog race condition

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The watchdog needs to be scheduled before we trigger the decode
operation, otherwise there is a risk that the decoder IRQ will be
called before we have schedule the watchdog. As a side effect, the
watchdog would never be cancelled and its function would be called
at an inappropriate time.

This was observed while running Fluster with GStreamer as a backend.
Some programming error would cause the decoder IRQ to be call very
quickly after the trigger. Later calls into the driver would deadlock
due to the unbalanced state.

Cc: stable@vger.kernel.org
Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion")
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
This commit is contained in:
Nicolas Dufresne 2022-08-18 22:33:06 +02:00 committed by Mauro Carvalho Chehab
parent 2801f6f30f
commit fe8b81fde6
1 changed files with 2 additions and 2 deletions
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4
drivers/staging/media/sunxi/cedrus/cedrus_dec.c
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@ -106,11 +106,11 @@ void cedrus_device_run(void *priv)
/* Trigger decoding if setup went well, bail out otherwise. */
if (!error) {
dev->dec_ops[ctx->current_codec]->trigger(ctx);
/* Start the watchdog timer. */
schedule_delayed_work(&dev->watchdog_work,
msecs_to_jiffies(2000));
dev->dec_ops[ctx->current_codec]->trigger(ctx);
} else {
v4l2_m2m_buf_done_and_job_finish(ctx->dev->m2m_dev,
ctx->fh.m2m_ctx,