Em Mon, 25 Apr 2016 13:36:57 +0200
Hans Verkuil <hverkuil@xxxxxxxxx> escreveu:
> Since my patch exchanges the sparse warning with a smatch warning, it's
> OK to take this one, with a few corrections:
>
> Please update the subject line (it says tvp686x instead of tw686x).
Gah...
>
> On 04/23/2016 11:23 AM, Mauro Carvalho Chehab wrote:
> > Depending on the compiler version, currently it produces the
> > following warnings:
> > tw686x-video.c: In function 'tw686x_video_init':
> > tw686x-video.c:65:543: warning: array subscript is above array bounds [-Warray-bounds]
> >
> > This is actually bogus with the current code, as it currently
> > hardcodes the framerate to 30 frames/sec, however a potential
> > use after the array size could happen when the driver adds support
> > for setting the framerate. So, fix it.
> >
> > Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
> > ---
> > drivers/media/pci/tw686x/tw686x-video.c | 15 +++++++++++++--
> > 1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/pci/tw686x/tw686x-video.c b/drivers/media/pci/tw686x/tw686x-video.c
> > index 118e9fac9f28..1ff59084ce08 100644
> > --- a/drivers/media/pci/tw686x/tw686x-video.c
> > +++ b/drivers/media/pci/tw686x/tw686x-video.c
> > @@ -61,8 +61,19 @@ static unsigned int tw686x_fields_map(v4l2_std_id std, unsigned int fps)
> > 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 0, 0
> > };
> >
> > - unsigned int i =
> > - (std & V4L2_STD_625_50) ? std_625_50[fps] : std_525_60[fps];
> > + unsigned int i;
> > +
> > + if (std & V4L2_STD_625_50) {
>
> Please test against 525_60 since that is the recommended test.
Both ways should work, but I'm OK with such change.
>
> > + if (unlikely(i > ARRAY_SIZE(std_625_50)))
>
> Please don't use 'unlikely'. It's pointless for code that is rarely used.
OK.
>
> Actually, the code is wrong: i is uninitialized here.
>
> It should be fps >= ARRAY_SIZE(std_625_50).
>
> In fact, I'd write it like this:
>
> i = std_625_50[(fps >= ARRAY_SIZE(std_625_50) ? 24 : fps];
I really don't like the above, as it has an unexplained magic
number on it. Also, "24" is wrong there.
So, I would go to the following enclosed patch.
Ezequiel,
Btw, I'm not seeing support for fps != 25 (or 30 fps) on this driver.
As the device seems to support setting the fps, you should be adding
support on it for VIDIOC_S_PARM and VIDIOC_G_PARM.
On both ioctls, the driver should return the actual framerate used.
So, you'll need to add a code that would convert from the 15 possible
framerate converter register settings to v4l2_fract.
>
> > + i = 14; /* 25 fps */
> > + else
> > + i = std_625_50[fps];
> > + } else {
> > + if (unlikely(i > ARRAY_SIZE(std_525_60)))
> > + i = 0; /* 30 fps */
> > + else
> > + i = std_525_60[fps];
> > + }
> >
> > return map[i];
> > }
> >
>
> Regards,
>
> Hans
Thanks,
Mauro
-
[media] tw686x: Don't go past array
Depending on the compiler version, currently it produces the
following warnings:
tw686x-video.c: In function 'tw686x_video_init':
tw686x-video.c:65:543: warning: array subscript is above array bounds [-Warray-bounds]
This is actually bogus with the current code, as it currently
hardcodes the framerate to 30 frames/sec, however a potential
use after the array size could happen when the driver adds support
for setting the framerate. So, fix it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>
diff --git a/drivers/media/pci/tw686x/tw686x-video.c b/drivers/media/pci/tw686x/tw686x-video.c
index 118e9fac9f28..9468fda69f3d 100644
--- a/drivers/media/pci/tw686x/tw686x-video.c
+++ b/drivers/media/pci/tw686x/tw686x-video.c
@@ -61,8 +61,17 @@ static unsigned int tw686x_fields_map(v4l2_std_id std, unsigned int fps)
8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 0, 0
};
- unsigned int i =
- (std & V4L2_STD_625_50) ? std_625_50[fps] : std_525_60[fps];
+ unsigned int i;
+
+ if (std & V4L2_STD_525_60) {
+ if (fps > ARRAY_SIZE(std_525_60))
+ fps = 30;
+ i = std_525_60[fps];
+ } else {
+ if (fps > ARRAY_SIZE(std_625_50))
+ fps = 25;
+ i = std_625_50[fps];
+ }
return map[i];
}
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