The watchdog needs to be schedule 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: [email protected]
Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion")
Signed-off-by: Nicolas Dufresne <[email protected]>
---
drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
index 3b6aa78a2985f..e7f7602a5ab40 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
@@ -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,
--
2.37.2
Hi Nicolas,
On Thu 18 Aug 22, 16:33, Nicolas Dufresne wrote:
> The watchdog needs to be schedule 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.
Good catch, thanks!
Reviewed-by: Paul Kocialkowski <[email protected]>
Cheers,
Paul
> Cc: [email protected]
> Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion")
> Signed-off-by: Nicolas Dufresne <[email protected]>
> ---
> drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> index 3b6aa78a2985f..e7f7602a5ab40 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> @@ -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,
> --
> 2.37.2
>
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
Dne četrtek, 18. avgust 2022 ob 22:33:06 CEST je Nicolas Dufresne napisal(a):
> The watchdog needs to be schedule 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: [email protected]
> Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion")
> Signed-off-by: Nicolas Dufresne <[email protected]>
Reviewed-by: Jernej Skrabec <[email protected]>
Best regards,
Jernej
> ---
> drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c index
> 3b6aa78a2985f..e7f7602a5ab40 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_dec.c
> @@ -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,
> --
> 2.37.2