From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julia Lawall Date: Tue, 23 Mar 2010 06:22:47 +0000 Subject: Re: [PATCH] drivers/media/video: avoid NULL dereference Message-Id: List-Id: References: <20100322231441.b7e33bf9.akpm@linux-foundation.org> In-Reply-To: <20100322231441.b7e33bf9.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Mark McClelland , Mauro Carvalho Chehab , linux-usb@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org From: Julia Lawall It seems impossible for ov to be NULL at this point. The semantic match that finds the problem is as follows: (http://coccinelle.lip6.fr/) // @r exists@ expression E, E1; identifier f; statement S1,S3; iterator iter; @@ if ((E = NULL && ...) || ...) { ... when != false ((E = NULL && ...) || ...) when != true ((E != NULL && ...) || ...) when != iter(E,...) S1 when != E = E1 ( sizeof(E->f) | * E->f ) ... when any return ...; } else S3 // Signed-off-by: Julia Lawall --- drivers/media/video/ov511.c | 5 ----- 1 files changed, 0 insertions(+), 5 deletions(-) diff --git a/drivers/media/video/ov511.c b/drivers/media/video/ov511.c index e0bce8d..dd1b1ac 100644 --- a/drivers/media/video/ov511.c +++ b/drivers/media/video/ov511.c @@ -5916,11 +5916,6 @@ ov51x_disconnect(struct usb_interface *intf) mutex_lock(&ov->lock); usb_set_intfdata (intf, NULL); - if (!ov) { - mutex_unlock(&ov->lock); - return; - } - /* Free device number */ ov511_devused &= ~(1 << ov->nr);