| Message ID | 20220818203308.439043-2-nicolas.dufresne@collabora.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1,1/3] media: cedrus: Fix watchdog race condition | expand |
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 <paul.kocialkowski@bootlin.com> Cheers, Paul > Cc: stable@vger.kernel.org > Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion") > Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> > --- > 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 >
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: stable@vger.kernel.org > Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion") > Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com> 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
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,
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: stable@vger.kernel.org Fixes: 7c38a551bda1 ("media: cedrus: Add watchdog for job completion") Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> --- drivers/staging/media/sunxi/cedrus/cedrus_dec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)