From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754075AbdJIJNY (ORCPT ); Mon, 9 Oct 2017 05:13:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42216 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754049AbdJIJNX (ORCPT ); Mon, 9 Oct 2017 05:13:23 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 6C8F3C0587E9 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=agruenba@redhat.com From: Andreas Gruenbacher To: Alexander Viro , Linus Torvalds Cc: Andreas Gruenbacher , Jan Kara , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, cluster-devel@redhat.com Subject: [PATCH] direct-io: Prevent NULL pointer access in submit_page_section Date: Mon, 9 Oct 2017 11:13:18 +0200 Message-Id: <20171009091318.26714-1-agruenba@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 09 Oct 2017 09:13:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the code added to function submit_page_section by commit b1058b981, sdio->bio can currently be NULL when calling dio_bio_submit. This then leads to a NULL pointer access in dio_bio_submit, so check for a NULL bio in submit_page_section before trying to submit it instead. Fixes xfstest generic/250 on gfs2. Signed-off-by: Andreas Gruenbacher Reviewed-by: Jan Kara --- fs/direct-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/direct-io.c b/fs/direct-io.c index 5fa2211e49ae..e0332da392d8 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -838,7 +838,8 @@ submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page, */ if (sdio->boundary) { ret = dio_send_cur_page(dio, sdio, map_bh); - dio_bio_submit(dio, sdio); + if (sdio->bio) + dio_bio_submit(dio, sdio); put_page(sdio->cur_page); sdio->cur_page = NULL; } -- 2.13.5