From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756128Ab3IKFVk (ORCPT ); Wed, 11 Sep 2013 01:21:40 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:13847 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754864Ab3IKE53 (ORCPT ); Wed, 11 Sep 2013 00:57:29 -0400 X-Authority-Analysis: v=2.0 cv=V4T/IJbi c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=Ciwy3NGCPMMA:10 a=xj2iYR5zRmMA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=4IVwp-sJ0kEA:10 a=VwQbUJbxAAAA:8 a=CZFccM69sVItBrhf7NQA:9 a=0kPLrQdw3YYA:10 a=jeBq3FmKZ4MA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-Id: <20130911042909.118010453@goodmis.org> User-Agent: quilt/0.60-1 Date: Wed, 11 Sep 2013 00:28:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: NeilBrown Subject: [101/251] md/raid10: remove use-after-free bug. References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0101-md-raid10-remove-use-after-free-bug.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown [ Upstream commit 0eb25bb027a100f5a9df8991f2f628e7d851bc1e ] We always need to be careful when calling generic_make_request, as it can start a chain of events which might free something that we are using. Here is one place I wasn't careful enough. If the wbio2 is not in use, then it might get freed at the first generic_make_request call. So perform all necessary tests first. This bug was introduced in 3.3-rc3 (24afd80d99) and can cause an oops, so fix is suitable for any -stable since then. Cc: stable@vger.kernel.org (3.3+) Signed-off-by: NeilBrown Signed-off-by: Steven Rostedt --- drivers/md/raid10.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index e2d5778..f40decb 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -2155,12 +2155,18 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio) d = r10_bio->devs[1].devnum; wbio = r10_bio->devs[1].bio; wbio2 = r10_bio->devs[1].repl_bio; + /* Need to test wbio2->bi_end_io before we call + * generic_make_request as if the former is NULL, + * the latter is free to free wbio2. + */ + if (wbio2 && !wbio2->bi_end_io) + wbio2 = NULL; if (wbio->bi_end_io) { atomic_inc(&conf->mirrors[d].rdev->nr_pending); md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9); generic_make_request(wbio); } - if (wbio2 && wbio2->bi_end_io) { + if (wbio2) { atomic_inc(&conf->mirrors[d].replacement->nr_pending); md_sync_acct(conf->mirrors[d].replacement->bdev, wbio2->bi_size >> 9); -- 1.7.10.4