[patch] fb: handle NULL pointers in framebuffer release

This function is called with a potential NULL pointer in
picolcd_init_framebuffer() and it causes a static checker warning.  This
used to handle NULL pointers when the picolcd code was written, but a
couple months later we added the "info->apertures" dereference.

Signed-off-by: Dan Carpenter <redacted>

diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
index 67afa9c..a55e366 100644
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c

@@ -80,6 +80,8 @@ EXPORT_SYMBOL(framebuffer_alloc);
  */
 void framebuffer_release(struct fb_info *info)
 {
+	if (!info)
+		return;
 	kfree(info->apertures);
 	kfree(info);
 }

On Mon, May 14, 2012 at 11:58:37PM +0300, Dan Carpenter wrote:

This function is called with a potential NULL pointer in
picolcd_init_framebuffer() and it causes a static checker warning.  This
used to handle NULL pointers when the picolcd code was written, but a
couple months later we added the "info->apertures" dereference.

Signed-off-by: Dan Carpenter <redacted>

Reviewed-by: Marcin Slusarz <redacted>

On 5/15/2012 4:58 AM, Dan Carpenter wrote:

And not like this:

+	if (info) {
+		if (info->apertures)
+			kfree(info->apertures);
+		kfree(info);
+	}

?

- Hein

On Tue, May 15, 2012 at 03:20:14PM +0800, Hein Tibosch wrote:

On 5/15/2012 4:58 AM, Dan Carpenter wrote:

quoted

This function is called with a potential NULL pointer in
picolcd_init_framebuffer() and it causes a static checker warning.  This
used to handle NULL pointers when the picolcd code was written, but a
couple months later we added the "info->apertures" dereference.

Signed-off-by: Dan Carpenter <redacted>

diff --git a/drivers/video/fbsysfs.c b/drivers/video/fbsysfs.c
index 67afa9c..a55e366 100644
--- a/drivers/video/fbsysfs.c
+++ b/drivers/video/fbsysfs.c

@@ -80,6 +80,8 @@ EXPORT_SYMBOL(framebuffer_alloc);
  */
 void framebuffer_release(struct fb_info *info)
 {
+	if (!info)
+		return;
 	kfree(info->apertures);
 	kfree(info);
 }

And not like this:

+	if (info) {
+		if (info->apertures)
+			kfree(info->apertures);
+		kfree(info);
+	}

Nah.  kfree() has a NULL check built in.  I think it would trigger
a checkpatch.pl warning?

regards,
dan carpenter

On 05/14/2012 08:58 PM, Dan Carpenter wrote:

This function is called with a potential NULL pointer in
picolcd_init_framebuffer() and it causes a static checker warning.  This
used to handle NULL pointers when the picolcd code was written, but a
couple months later we added the "info->apertures" dereference.

Signed-off-by: Dan Carpenter <redacted>

Applied.


Thanks,

Florian Tobias Schandinat