On Tue, Jan 11, 2022 at 12:46:56AM +0200, Sakari Ailus wrote:
> Pointers V4L2 pixelformat and dataformat fields in a few packed structs
> are directly passed to printk family of functions. This could result in an
> unaligned access albeit no such possibility appears to exist at the
> moment i.e. this clang warning appears to be a false positive.
>
> Address the warning by copying the pixelformat or dataformat value to a
> local variable first.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Fixes: e927e1e0f0dd ("v4l: ioctl: Use %p4cc printk modifier to print FourCC codes")
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> Hi Andy, Nick,
>
> How about this one?
>
> I believe it does address the clang warning although I haven't tested it.
With addressed comments, pointed by Nick,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Thanks!
Note, applying this doesn't automatically discard my patch.
> drivers/media/v4l2-core/v4l2-ioctl.c | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 9ac557b8e146..642cb90f457c 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -279,8 +279,8 @@ static void v4l_print_format(const void *arg, bool write_only)
> const struct v4l2_vbi_format *vbi;
> const struct v4l2_sliced_vbi_format *sliced;
> const struct v4l2_window *win;
> - const struct v4l2_sdr_format *sdr;
> const struct v4l2_meta_format *meta;
> + u32 pixelformat;
> u32 planes;
> unsigned i;
>
> @@ -299,8 +299,9 @@ static void v4l_print_format(const void *arg, bool write_only)
> case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> mp = &p->fmt.pix_mp;
> + pixelformat = mp->pixelformat;
> pr_cont(", width=%u, height=%u, format=%p4cc, field=%s, colorspace=%d, num_planes=%u, flags=0x%x, ycbcr_enc=%u, quantization=%u, xfer_func=%u\n",
> - mp->width, mp->height, &mp->pixelformat,
> + mp->width, mp->height, &pixelformat,
> prt_names(mp->field, v4l2_field_names),
> mp->colorspace, mp->num_planes, mp->flags,
> mp->ycbcr_enc, mp->quantization, mp->xfer_func);
> @@ -343,14 +344,15 @@ static void v4l_print_format(const void *arg, bool write_only)
> break;
> case V4L2_BUF_TYPE_SDR_CAPTURE:
> case V4L2_BUF_TYPE_SDR_OUTPUT:
> - sdr = &p->fmt.sdr;
> - pr_cont(", pixelformat=%p4cc\n", &sdr->pixelformat);
> + pixelformat = p->fmt.sdr.pixelformat;
> + pr_cont(", pixelformat=%p4cc\n", &pixelformat);
> break;
> case V4L2_BUF_TYPE_META_CAPTURE:
> case V4L2_BUF_TYPE_META_OUTPUT:
> meta = &p->fmt.meta;
> + pixelformat = meta->dataformat;
> pr_cont(", dataformat=%p4cc, buffersize=%u\n",
> - &meta->dataformat, meta->buffersize);
> + &pixelformat, meta->buffersize);
> break;
> }
> }
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
