On Fri, Feb 02, 2018 at 06:32:23AM -0600, Gustavo A. R. Silva wrote:
> _minor_ is being dereferenced before it is null checked, hence there
> is a potential null pointer dereference. Fix this by moving the pointer
> dereference after _minor_ has been null checked.
>
> Fixes: 024ad8df763f ("drm/msm: add a5xx specific debugfs")
> Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
> ---
>
> I wonder if a better solution for this would be to WARN_ON in case _minor_
> happens to be NULL and return -EINVAL, instead of just returning zero.
>
> Something like:
>
> struct drm_device *dev;
>
> if (WARN_ON(!minor)
> return -EINVAL;
>
> dev = minor->dev;
>
> What do you think?
In my opinion everything in debugfs is optional. I'm not sure if it is even
possible for dev->primary, dev->render or dev->control to be NULL from the DRM
core but if so I think the failure should be silent.
Jordan
>
> drivers/gpu/drm/msm/adreno/a5xx_debugfs.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_debugfs.c b/drivers/gpu/drm/msm/adreno/a5xx_debugfs.c
> index 6b27941..059ec7d 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_debugfs.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_debugfs.c
> @@ -159,13 +159,15 @@ DEFINE_SIMPLE_ATTRIBUTE(reset_fops, NULL, reset_set, "%llx\n");
>
> int a5xx_debugfs_init(struct msm_gpu *gpu, struct drm_minor *minor)
> {
> - struct drm_device *dev = minor->dev;
> + struct drm_device *dev;
> struct dentry *ent;
> int ret;
>
> if (!minor)
> return 0;
>
> + dev = minor->dev;
> +
> ret = drm_debugfs_create_files(a5xx_debugfs_list,
> ARRAY_SIZE(a5xx_debugfs_list),
> minor->debugfs_root, minor);
> --
> 2.7.4
>
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