Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S946283AbdDTOHY (ORCPT ); Thu, 20 Apr 2017 10:07:24 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:36126 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S946265AbdDTOHW (ORCPT ); Thu, 20 Apr 2017 10:07:22 -0400 From: Colin King To: Paolo Valente , Jens Axboe , linux-block@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][-next] block, bfq: don't dereference bic before null checking it Date: Thu, 20 Apr 2017 15:07:18 +0100 Message-Id: <20170420140718.19694-1-colin.king@canonical.com> X-Mailer: git-send-email 2.11.0 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 988 Lines: 34 From: Colin Ian King The call to bfq_check_ioprio_change will dereference bic, however, the null check for bic is after this call. Move the the null check on bic to before the call to avoid any potential null pointer dereference issues. Detected by CoverityScan, CID#1430138 ("Dereference before null check") Signed-off-by: Colin Ian King --- block/bfq-iosched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 6d14f18c0d45..bd8499ef157c 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4401,11 +4401,11 @@ static int bfq_get_rq_private(struct request_queue *q, struct request *rq, spin_lock_irq(&bfqd->lock); - bfq_check_ioprio_change(bic, bio); - if (!bic) goto queue_fail; + bfq_check_ioprio_change(bic, bio); + bfq_bic_update_cgroup(bic, bio); bfqq = bfq_get_bfqq_handle_split(bfqd, bic, bio, false, is_sync, -- 2.11.0