From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754428Ab0E0Mcx (ORCPT ); Thu, 27 May 2010 08:32:53 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:51744 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751469Ab0E0Mcu (ORCPT ); Thu, 27 May 2010 08:32:50 -0400 Date: Thu, 27 May 2010 14:32:45 +0200 (CEST) From: Julia Lawall To: "David S. Miller" , Grant Likely , sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, kernel-janitors@vger.kernel.org Subject: [PATCH 3/11] arch/sparc/kernel: Eliminate what looks like a NULL pointer dereference Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Julia Lawall At the point of the test, action cannot be NULL, as it has been dereferenced in the code just above. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // @r exists@ expression E,E1; identifier f; statement S1,S2,S3; @@ if ((E == NULL && ...) || ...) { ... when != if (...) S1 else S2 when != E = E1 * E->f ... when any } else S3 // Signed-off-by: Julia Lawall --- arch/sparc/kernel/sun4d_irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sparc/kernel/sun4d_irq.c b/arch/sparc/kernel/sun4d_irq.c index ab036a7..e11b461 100644 --- a/arch/sparc/kernel/sun4d_irq.c +++ b/arch/sparc/kernel/sun4d_irq.c @@ -183,7 +183,7 @@ void sun4d_free_irq(unsigned int irq, void *dev_id) goto out_unlock; } - if (action && tmp) + if (tmp) tmp->next = action->next; else *actionp = action->next;