Hello, On Mon, Feb 07, 2022 at 10:52:00AM +0100, Alexander Stein wrote: > Am Samstag, 5. Februar 2022, 08:51:51 CET schrieb Dorota Czaplejewicz: > > On Sat, 5 Feb 2022 06:07:37 +0200 Laurent Pinchart wrote: > > > On Fri, Feb 04, 2022 at 01:15:10PM +0100, Alexander Stein wrote: > > > > From: Dorota Czaplejewicz <dorota.czaplejewicz@xxxxxxx> > > > > > > > > imx_media_find_mbus_format has NULL as a valid return value, > > > > therefore the caller should take it into account. > > > > > > > > Signed-off-by: Dorota Czaplejewicz <dorota.czaplejewicz@xxxxxxx> > > > > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> > > > > --- > > > > > > > > drivers/staging/media/imx/imx-media-utils.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/drivers/staging/media/imx/imx-media-utils.c > > > > b/drivers/staging/media/imx/imx-media-utils.c index > > > > 32aaa2e81bea..e0a256a08c3b 100644 > > > > --- a/drivers/staging/media/imx/imx-media-utils.c > > > > +++ b/drivers/staging/media/imx/imx-media-utils.c > > > > @@ -544,6 +544,9 @@ static int imx56_media_mbus_fmt_to_pix_fmt(struct > > > > v4l2_pix_format *pix,> > > > > > cc = imx_media_find_mbus_format(code, PIXFMT_SEL_YUV); > > > > > > The code passed to the function comes from the previous line: > > > imx_media_enum_mbus_formats(&code, 0, PIXFMT_SEL_YUV); > > > > > > As far as I can tell, this is guaranteed to return a code that will > > > result in imx_media_find_mbus_format() returning a non-NULL pointer. > > > > While I am not well-versed in the implicit code style of the kernel, I > > decided to leave it in because it makes the code more locally legible. With > > a check here, even a non-functional one, there's no need to understand the > > internals of `imx_media_find_mbus_format` that are only implicit. That > > makes the code less surprising when interested only in the outer function. > > > > The other advantage of a check is becoming robust against future changes to > > `imx_media_find_mbus_format` itself. > > > > I don't have a strong preference about keeping or leaving this patch, but if > > this check was there in the first place, I wouldn't have spent time trying > > to figure out whether there's a bug here. > > Laurent, thanks for your feedback. > I'm on Dorota's side here. While you are right that the code from > imx_media_enum_mbus_formats(&code, 0, PIXFMT_SEL_YUV); > is guaranteed to return something. I don't lnek this implicit assumption over > 2 function calls. Better be safe than sorry. For that reason code should be > initialized as well. Will create a patch for that. I'm fine with hardening the code even if the issue can't occur at the moment. -- Regards, Laurent Pinchart
