[PATCH v2] drm/fb-helper: Do the 'max_conn_count' zero check

[PATCH v2] drm/fb-helper: Do the 'max_conn_count' zero check

[Xiubo Li]

Since we cannot make sure the 'max_conn_count' will always be none
zero from the users, and then if max_conn_count equals to zero, the
kcalloc() will return ZERO_SIZE_PTR, which equals to ((void *)16).

So this patch fix this with just doing the 'max_conn_count' zero check
in the front of drm_fb_helper_init().

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
CC: Jani Nikula <jani.nikula@linux.intel.com>
---
 drivers/gpu/drm/drm_fb_helper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 3d13ca6e2..a0d286c 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -514,6 +514,9 @@ int drm_fb_helper_init(struct drm_device *dev,
 	struct drm_crtc *crtc;
 	int i;
 
+	if (!max_conn_count)
+		return -EINVAL;
+
 	fb_helper->dev = dev;
 
 	INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
-- 
1.8.4

Re: [PATCH v2] drm/fb-helper: Do the 'max_conn_count' zero check

[Daniel Vetter]

On Mon, Mar 10, 2014 at 09:33:58AM +0800, Xiubo Li wrote:
> Since we cannot make sure the 'max_conn_count' will always be none
> zero from the users, and then if max_conn_count equals to zero, the
> kcalloc() will return ZERO_SIZE_PTR, which equals to ((void *)16).
> 
> So this patch fix this with just doing the 'max_conn_count' zero check
> in the front of drm_fb_helper_init().
> 
> Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
> CC: Jani Nikula <jani.nikula@linux.intel.com>

Makes sense.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/drm_fb_helper.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 3d13ca6e2..a0d286c 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -514,6 +514,9 @@ int drm_fb_helper_init(struct drm_device *dev,
>  	struct drm_crtc *crtc;
>  	int i;
>  
> +	if (!max_conn_count)
> +		return -EINVAL;
> +
>  	fb_helper->dev = dev;
>  
>  	INIT_LIST_HEAD(&fb_helper->kernel_fb_list);
> -- 
> 1.8.4
> 
> 
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> dri-devel@lists.freedesktop.org
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch