On 09/12/2017 10:09 PM, Arnd Bergmann wrote: > While experimenting with older compiler versions, I ran > into a warning that no longer shows up on gcc-4.8 or newer: > > drivers/media/platform/s3c-camif/camif-capture.c: In function '__camif_subdev_try_format': > drivers/media/platform/s3c-camif/camif-capture.c:1265:25: error: array subscript is below array bounds > > This is an off-by-one bug, leading to an access before the start of the > array, while newer compilers silently assume this undefined behavior > cannot happen and leave the loop at index 0 if no other entry matches. > > Since the code is not only wrong, but also has no effect besides the > out-of-bounds access, this patch just removes it. > > I found an existing gcc bug for it and added a reduced version > of the function there. > > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69249#c3 > Fixes: babde1c243b2 ("[media] V4L: Add driver for S3C24XX/S3C64XX SoC series camera interface") > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > drivers/media/platform/s3c-camif/camif-capture.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/drivers/media/platform/s3c-camif/camif-capture.c b/drivers/media/platform/s3c-camif/camif-capture.c > index 25c7a7d42292..c6921f6a5a6a 100644 > --- a/drivers/media/platform/s3c-camif/camif-capture.c > +++ b/drivers/media/platform/s3c-camif/camif-capture.c > @@ -1256,17 +1256,10 @@ static void __camif_subdev_try_format(struct camif_dev *camif, > { > const struct s3c_camif_variant *variant = camif->variant; > const struct vp_pix_limits *pix_lim; > - int i = ARRAY_SIZE(camif_mbus_formats); > > /* FIXME: constraints against codec or preview path ? */ > pix_lim = &variant->vp_pix_limits[VP_CODEC]; > > - while (i-- >= 0) > - if (camif_mbus_formats[i] == mf->code) > - break; > - > - mf->code = camif_mbus_formats[i]; Interesting finding... the function needs to ensure mf->code is set to one of supported values by the driver, so instead of removing how about changing the above line to: if (i < 0) mf->code = camif_mbus_formats[0]; ? -- Thanks, Sylwester
