From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Brunel Subject: [PATCH] drivers/video: Bad error test before a dereference Date: Fri, 26 Sep 2008 15:53:44 +0200 Message-ID: <200809261553.45301.brunel@diku.dk> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: nicolas.ferre@atmel.com, adaplas@gmail.com, linux-fbdev-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org The error test that follows the call to backlight_device_register semms not to concern the right variable. A simplified version of the semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // @def0@ expression x; position p0; @@ x@p0 = backlight_device_register(...) @protected@ expression def0.x,E; position def0.p0; position p; statement S; @@ x@p0 ... when != x = E if (!IS_ERR(x) && ...) {<... x@p ...>} else S @unprotected@ expression def0.x; identifier fld; position def0.p0; position p != protected.p; @@ x@p0 ... when != x = E * x@p->fld // Signed-off-by: Julien Brunel Signed-off-by: Julia Lawall --- drivers/video/atmel_lcdfb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -u -p a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c --- a/drivers/video/atmel_lcdfb.c +++ b/drivers/video/atmel_lcdfb.c @@ -132,7 +132,7 @@ static void init_backlight(struct atmel_ bl = backlight_device_register("backlight", &sinfo->pdev->dev, sinfo, &atmel_lcdc_bl_ops); - if (IS_ERR(sinfo->backlight)) { + if (IS_ERR(bl)) { dev_err(&sinfo->pdev->dev, "error %ld on backlight register\n", PTR_ERR(bl)); return;