From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751460AbZJQGdr (ORCPT ); Sat, 17 Oct 2009 02:33:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751284AbZJQGdq (ORCPT ); Sat, 17 Oct 2009 02:33:46 -0400 Received: from mgw1.diku.dk ([130.225.96.91]:59114 "EHLO mgw1.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871AbZJQGdp (ORCPT ); Sat, 17 Oct 2009 02:33:45 -0400 Date: Sat, 17 Oct 2009 08:33:47 +0200 (CEST) From: Julia Lawall To: Kyle McMartin , Jaroslav Kysela , Takashi Iwai , linux-parisc@vger.kernel.org, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH 3/14] sound/parisc: Move dereference after NULL test 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 If the NULL test on h is needed in snd_harmony_mixer_init, then the dereference should be after the NULL test. Actually, there is a sequence of calls: snd_harmony_create, then snd_harmony_pcm_init, and then snd_harmony_mixer_init. snd_harmony_create initializes h, but may indeed leave it as NULL. There was no NULL test at the beginning of snd_harmony_pcm_init, so I have added one. The NULL test in snd_harmony_mixer_init is then not necessary, but in case the ordering of the calls changes, I have left it, and moved the dereference after it. A simplified version of the semantic match that detects this problem is as follows (http://coccinelle.lip6.fr/): // @match exists@ expression x, E; identifier fld; @@ * x->fld ... when != \(x = E\|&x\) * x == NULL // Signed-off-by: Julia Lawall --- sound/parisc/harmony.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/sound/parisc/harmony.c b/sound/parisc/harmony.c index e924492..f47f9e2 100644 --- a/sound/parisc/harmony.c +++ b/sound/parisc/harmony.c @@ -624,6 +624,9 @@ snd_harmony_pcm_init(struct snd_harmony *h) struct snd_pcm *pcm; int err; + if (snd_BUG_ON(!h)) + return -EINVAL; + harmony_disable_interrupts(h); err = snd_pcm_new(h->card, "harmony", 0, 1, 1, &pcm); @@ -865,11 +868,12 @@ snd_harmony_mixer_reset(struct snd_harmony *h) static int __devinit snd_harmony_mixer_init(struct snd_harmony *h) { - struct snd_card *card = h->card; + struct snd_card *card; int idx, err; if (snd_BUG_ON(!h)) return -EINVAL; + card = h->card; strcpy(card->mixername, "Harmony Gain control interface"); for (idx = 0; idx < HARMONY_CONTROLS; idx++) {