diff mbox series

[5/7] media: cedrus: h265: Add a couple of error checks

Message ID 20220620175517.648767-6-jernej.skrabec@gmail.com (mailing list archive)
State New, archived
Headers show
Series media: cedrus: h265: Implement tiles support | expand

Commit Message

Jernej Škrabec June 20, 2022, 5:55 p.m. UTC
Now that we have infrastructure for reporting errors, let's add two
checks, which will make sure slice can be actually decoded.

Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
---
 drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Ezequiel Garcia July 11, 2022, 9:31 p.m. UTC | #1
On Mon, Jun 20, 2022 at 07:55:15PM +0200, Jernej Skrabec wrote:
> Now that we have infrastructure for reporting errors, let's add two
> checks, which will make sure slice can be actually decoded.
> 
> Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
> ---
>  drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> index cfde4ccf6011..99020b9f9ff8 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c

Now that you've allowed setup to fail, I would suggest
to have some documentation/comments on struct cedrus_dec_ops,
to set the expectation/rules for each ops, including the
call paths for each operation, which of them are allowed to sleep,
etc.

> @@ -435,9 +435,17 @@ static int cedrus_h265_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
>  	 * instead of start of slice data. Padding is 8 bits at most (one bit set to 1 and
>  	 * at most seven bits set to 0), so we have to inspect only one byte before slice data.
>  	 */
> +
> +	if (slice_params->data_byte_offset == 0)
> +		return -EOPNOTSUPP;
> +

AFAICS, cedrus_h265_setup is called from .device_run.
We've been discussing control validation before, and I think the
ideal place to do that is v4l2_ctrl_ops.s_ctrl, if that's
at all possible.

Driver's mem2mem device_run are executed in the context
of a work_struct and the failure won't really get reported
up the stack.

>  	padding = (u8 *)vb2_plane_vaddr(&run->src->vb2_buf, 0) +
>  		slice_params->data_byte_offset - 1;
>  
> +	/* at least one bit must be set in that byte */
> +	if (*padding == 0)
> +		return -EINVAL;
> +

Maybe this is something to check at cedrus_buf_prepare(),
when the buffer is queued?

Thanks,
Ezequiel

>  	for (count = 0; count < 8; count++)
>  		if (*padding & (1 << count))
>  			break;
> -- 
> 2.36.1
>
Jernej Škrabec July 12, 2022, 9:25 p.m. UTC | #2
Hi Ezequiel.

Dne ponedeljek, 11. julij 2022 ob 23:31:11 CEST je Ezequiel Garcia napisal(a):
> On Mon, Jun 20, 2022 at 07:55:15PM +0200, Jernej Skrabec wrote:
> > Now that we have infrastructure for reporting errors, let's add two
> > checks, which will make sure slice can be actually decoded.
> > 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
> > ---
> > 
> >  drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c index
> > cfde4ccf6011..99020b9f9ff8 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> 
> Now that you've allowed setup to fail, I would suggest
> to have some documentation/comments on struct cedrus_dec_ops,
> to set the expectation/rules for each ops, including the
> call paths for each operation, which of them are allowed to sleep,
> etc.

Documentation can be always added, but it should be separate patch.

> 
> > @@ -435,9 +435,17 @@ static int cedrus_h265_setup(struct cedrus_ctx *ctx,
> > struct cedrus_run *run)> 
> >  	 * instead of start of slice data. Padding is 8 bits at most (one 
bit
> >  	 set to 1 and * at most seven bits set to 0), so we have to 
inspect
> >  	 only one byte before slice data. */
> > 
> > +
> > +	if (slice_params->data_byte_offset == 0)
> > +		return -EOPNOTSUPP;
> > +
> 
> AFAICS, cedrus_h265_setup is called from .device_run.
> We've been discussing control validation before, and I think the
> ideal place to do that is v4l2_ctrl_ops.s_ctrl, if that's
> at all possible.

Yeah, this particular check can be moved to s_ctrl handler.

> 
> Driver's mem2mem device_run are executed in the context
> of a work_struct and the failure won't really get reported
> up the stack.

Well, at least there will be a notice in dmesg. Not ideal, I know.

> 
> >  	padding = (u8 *)vb2_plane_vaddr(&run->src->vb2_buf, 0) +
> >  	
> >  		slice_params->data_byte_offset - 1;
> > 
> > +	/* at least one bit must be set in that byte */
> > +	if (*padding == 0)
> > +		return -EINVAL;
> > +
> 
> Maybe this is something to check at cedrus_buf_prepare(),
> when the buffer is queued?

I don't think so. This check is HEVC specific, but cedrus_buf_prepare() is not 
and we need to have slice control ready, which I'm not sure is the case for 
cedrus_buf_prepare().

Best regards,
Jernej

> 
> Thanks,
> Ezequiel
> 
> >  	for (count = 0; count < 8; count++)
> >  	
> >  		if (*padding & (1 << count))
> >  		
> >  			break;
> > 
> > --
> > 2.36.1
Ezequiel Garcia July 13, 2022, 4:45 p.m. UTC | #3
Hi Jernej,

On Tue, Jul 12, 2022 at 11:25:00PM +0200, Jernej Škrabec wrote:
> Hi Ezequiel.
> 
> Dne ponedeljek, 11. julij 2022 ob 23:31:11 CEST je Ezequiel Garcia napisal(a):
> > On Mon, Jun 20, 2022 at 07:55:15PM +0200, Jernej Skrabec wrote:
> > > Now that we have infrastructure for reporting errors, let's add two
> > > checks, which will make sure slice can be actually decoded.
> > > 
> > > Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
> > > ---
> > > 
> > >  drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > > b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c index
> > > cfde4ccf6011..99020b9f9ff8 100644
> > > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > 
> > Now that you've allowed setup to fail, I would suggest
> > to have some documentation/comments on struct cedrus_dec_ops,
> > to set the expectation/rules for each ops, including the
> > call paths for each operation, which of them are allowed to sleep,
> > etc.
> 
> Documentation can be always added, but it should be separate patch.
> 

Of course, this wasn't a comment meant to block the patch in any way.

> > 
> > > @@ -435,9 +435,17 @@ static int cedrus_h265_setup(struct cedrus_ctx *ctx,
> > > struct cedrus_run *run)> 
> > >  	 * instead of start of slice data. Padding is 8 bits at most (one 
> bit
> > >  	 set to 1 and * at most seven bits set to 0), so we have to 
> inspect
> > >  	 only one byte before slice data. */
> > > 
> > > +
> > > +	if (slice_params->data_byte_offset == 0)
> > > +		return -EOPNOTSUPP;
> > > +
> > 
> > AFAICS, cedrus_h265_setup is called from .device_run.
> > We've been discussing control validation before, and I think the
> > ideal place to do that is v4l2_ctrl_ops.s_ctrl, if that's
> > at all possible.
> 
> Yeah, this particular check can be moved to s_ctrl handler.
> 
> > 
> > Driver's mem2mem device_run are executed in the context
> > of a work_struct and the failure won't really get reported
> > up the stack.
> 
> Well, at least there will be a notice in dmesg. Not ideal, I know.
> 
> > 
> > >  	padding = (u8 *)vb2_plane_vaddr(&run->src->vb2_buf, 0) +
> > >  	
> > >  		slice_params->data_byte_offset - 1;
> > > 
> > > +	/* at least one bit must be set in that byte */
> > > +	if (*padding == 0)
> > > +		return -EINVAL;
> > > +
> > 
> > Maybe this is something to check at cedrus_buf_prepare(),
> > when the buffer is queued?
> 
> I don't think so. This check is HEVC specific, but cedrus_buf_prepare() is not 
> and we need to have slice control ready, which I'm not sure is the case for 
> cedrus_buf_prepare().
> 

Hm... this is indeed a special case. The buffer contents
depend on a control, and both buffer and control are part of the same
request.

At least the decoding job would fail, and would get signaled
by the dequeued CAPTURE buffers and the V4L2_BUF_FLAG_ERROR flag,
which makes perfect sense.

In general vb2_ops.buf_prepare() is called for each
buffer (either through VIDIOC_QBUF or through MEDIA_REQUEST_IOC_QUEUE),
so for some buffer validations .buf_prepare() _might_ work better 
than .device_run for validation.

In any case, the patch looks good, I don't think these
comments should block the patch:

Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

Thanks,
Ezequiel

> Best regards,
> Jernej
> 
> > 
> > Thanks,
> > Ezequiel
> > 
> > >  	for (count = 0; count < 8; count++)
> > >  	
> > >  		if (*padding & (1 << count))
> > >  		
> > >  			break;
> > > 
> > > --
> > > 2.36.1
> 
>
diff mbox series

Patch

diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
index cfde4ccf6011..99020b9f9ff8 100644
--- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
@@ -435,9 +435,17 @@  static int cedrus_h265_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
 	 * instead of start of slice data. Padding is 8 bits at most (one bit set to 1 and
 	 * at most seven bits set to 0), so we have to inspect only one byte before slice data.
 	 */
+
+	if (slice_params->data_byte_offset == 0)
+		return -EOPNOTSUPP;
+
 	padding = (u8 *)vb2_plane_vaddr(&run->src->vb2_buf, 0) +
 		slice_params->data_byte_offset - 1;
 
+	/* at least one bit must be set in that byte */
+	if (*padding == 0)
+		return -EINVAL;
+
 	for (count = 0; count < 8; count++)
 		if (*padding & (1 << count))
 			break;