On 05/03/2018 01:43 PM, Dan Carpenter wrote:
> [ This code is five years old now. It's so weird to me that the warning
> is showing up in my new warnings pile. Perhaps this wasn't included
> in my allmodconfig before? - dan ]
Might be, the bug found is real. The module is normally disabled anyway
for other reasons.
> Hello Sylwester Nawrocki,
>
> The patch 34947b8aebe3: "[media] exynos4-is: Add the FIMC-IS ISP
> capture DMA driver" from Dec 20, 2013, leads to the following static
> checker warning:
>
> drivers/media/platform/exynos4-is/fimc-isp-video.c:408 isp_video_try_fmt_mplane()
> error: NULL dereference inside function '__isp_video_try_fmt(isp, &f->fmt.pix_mp, (0))()'.
>
> drivers/media/platform/exynos4-is/fimc-isp-video.c
> 383 static void __isp_video_try_fmt(struct fimc_isp *isp,
> 384 struct v4l2_pix_format_mplane *pixm,
> 385 const struct fimc_fmt **fmt)
> 386 {
> 387 *fmt = fimc_isp_find_format(&pixm->pixelformat, NULL, 2);
> ^^^^
> Unchecked dereference. We're not allowed to pass a NULL "fmt".
>
> 388
> 389 pixm->colorspace = V4L2_COLORSPACE_SRGB;
> 390 pixm->field = V4L2_FIELD_NONE;
> 391 pixm->num_planes = (*fmt)->memplanes;
> 392 pixm->pixelformat = (*fmt)->fourcc;
> 393 /*
> 394 * TODO: double check with the docmentation these width/height
> 395 * constraints are correct.
> 396 */
> 397 v4l_bound_align_image(&pixm->width, FIMC_ISP_SOURCE_WIDTH_MIN,
> 398 FIMC_ISP_SOURCE_WIDTH_MAX, 3,
> 399 &pixm->height, FIMC_ISP_SOURCE_HEIGHT_MIN,
> 400 FIMC_ISP_SOURCE_HEIGHT_MAX, 0, 0);
> 401 }
> 402
> 403 static int isp_video_try_fmt_mplane(struct file *file, void *fh,
> 404 struct v4l2_format *f)
> 405 {
> 406 struct fimc_isp *isp = video_drvdata(file);
> 407
> 408 __isp_video_try_fmt(isp, &f->fmt.pix_mp, NULL);
> ^^^^
> And yet here we are.
>
> 409 return 0;
> 410 }
We may need something like:
----8<----
diff --git a/drivers/media/platform/exynos4-is/fimc-isp-video.c b/drivers/media/platform/exynos4-is/fimc-isp-video.c
index 55ba696b8cf4..a920164f53f1 100644
--- a/drivers/media/platform/exynos4-is/fimc-isp-video.c
+++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c
@@ -384,12 +384,17 @@ static void __isp_video_try_fmt(struct fimc_isp *isp,
struct v4l2_pix_format_mplane *pixm,
const struct fimc_fmt **fmt)
{
- *fmt = fimc_isp_find_format(&pixm->pixelformat, NULL, 2);
+ const struct fimc_fmt *__fmt;
+
+ __fmt = fimc_isp_find_format(&pixm->pixelformat, NULL, 2);
+
+ if (fmt)
+ *fmt = __fmt;
pixm->colorspace = V4L2_COLORSPACE_SRGB;
pixm->field = V4L2_FIELD_NONE;
- pixm->num_planes = (*fmt)->memplanes;
- pixm->pixelformat = (*fmt)->fourcc;
+ pixm->num_planes = __fmt->memplanes;
+ pixm->pixelformat = __fmt->fourcc;
/*
* TODO: double check with the docmentation these width/height
* constraints are correct.
----8<----
I will post the patch to clear the warning.
--
Thanks,
Sylwester
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