Aug 27 2010

V4L/DVB: drivers/media/video/em28xx: Remove potential NULL dereference 

Author: Julia Lawall <julia@diku.dk>

If the NULL test is necessary, the initialization involving a dereference of
the tested value should be moved after the NULL test.

The sematic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
type T;
expression E;
identifier i,fld;
statement S;
@@

- T i = E->fld;
+ T i;
  ... when != E
      when != i
  if (E == NULL) S
+ i = E->fld;
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Mauro Carvalho Chehab 

---
 drivers/media/video/em28xx/em28xx-video.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
 
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index 7b9ec6e..95a4b60 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -277,12 +277,13 @@ static void em28xx_copy_vbi(struct em28xx *dev,
 {
 	void *startwrite, *startread;
 	int  offset;
-	int bytesperline = dev->vbi_width;
+	int bytesperline;
 
 	if (dev == NULL) {
 		em28xx_isocdbg("dev is null\n");
 		return;
 	}
+	bytesperline = dev->vbi_width;
 
 	if (dma_q == NULL) {
 		em28xx_isocdbg("dma_q is null\n");

qlambert