From patchwork Mon Oct 9 09:13:18 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 9992409 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BD8CB603B5 for ; Mon, 9 Oct 2017 09:13:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AFC4628741 for ; Mon, 9 Oct 2017 09:13:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A49A028745; Mon, 9 Oct 2017 09:13:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B3D5728741 for ; Mon, 9 Oct 2017 09:13:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754054AbdJIJNY (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 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6C8F3C0587E9; Mon, 9 Oct 2017 09:13:23 +0000 (UTC) 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 Received: from max.home.com (unknown [10.36.118.12]) by smtp.corp.redhat.com (Postfix) with ESMTP id D5D6961526; Mon, 9 Oct 2017 09:13:19 +0000 (UTC) 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-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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; }