From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753554Ab2CDMKh (ORCPT ); Sun, 4 Mar 2012 07:10:37 -0500 Received: from mail-pw0-f46.google.com ([209.85.160.46]:64500 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753284Ab2CDMKf (ORCPT ); Sun, 4 Mar 2012 07:10:35 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of linkinjeon@gmail.com designates 10.68.218.130 as permitted sender) smtp.mail=linkinjeon@gmail.com; dkim=pass header.i=linkinjeon@gmail.com From: Namjae Jeon To: axboe@kernel.dk, tj@kernel.org Cc: linux-kernel@vger.kernel.org, Namjae Jeon Subject: [PATCH] cfq: fix NULL pointer dereference in cfq_choose_cfqg. Date: Sun, 4 Mar 2012 07:10:26 -0500 Message-Id: <1330863026-2696-1-git-send-email-linkinjeon@gmail.com> X-Mailer: git-send-email 1.7.5.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I found null pointer dereferencing possibility while reviewing. If cfq_get_next_cfqg return null by RB_EMPTY_ROOT, null pointer dereferencing error can occur. Signed-off-by: Namjae Jeon --- block/cfq-iosched.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index d0ba505..d924272 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2306,7 +2306,7 @@ static void cfq_choose_cfqg(struct cfq_data *cfqd) cfqd->serving_group = cfqg; /* Restore the workload type data */ - if (cfqg->saved_workload_slice) { + if (!cfqg && cfqg->saved_workload_slice) { cfqd->workload_expires = jiffies + cfqg->saved_workload_slice; cfqd->serving_type = cfqg->saved_workload; cfqd->serving_prio = cfqg->saved_serving_prio; -- 1.7.5.4