From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162109Ab2GLWnW (ORCPT ); Thu, 12 Jul 2012 18:43:22 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:44509 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162054Ab2GLWnI (ORCPT ); Thu, 12 Jul 2012 18:43:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, majianpeng , NeilBrown Subject: [ 131/187] md/raid5: In ops_run_io, inc nr_pending before calling md_wait_for_blocked_rdev Date: Thu, 12 Jul 2012 15:34:47 -0700 Message-Id: <20120712191534.530236769@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: majianpeng commit 1850753d2e6d9ca7856581ca5d3cf09521e6a5d7 upstream. In ops_run_io(), the call to md_wait_for_blocked_rdev will decrement nr_pending so we lose the reference we hold on the rdev. So atomic_inc it first to maintain the reference. This bug was introduced by commit 73e92e51b7969ef5477d md/raid5. Don't write to known bad block on doubtful devices. which appeared in 3.0, so patch is suitable for stable kernels since then. Signed-off-by: majianpeng Signed-off-by: NeilBrown Signed-off-by: Greg Kroah-Hartman --- drivers/md/raid5.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -583,6 +583,12 @@ static void ops_run_io(struct stripe_hea * a chance*/ md_check_recovery(conf->mddev); } + /* + * Because md_wait_for_blocked_rdev + * will dec nr_pending, we must + * increment it first. + */ + atomic_inc(&rdev->nr_pending); md_wait_for_blocked_rdev(rdev, conf->mddev); } else { /* Acknowledged bad block - skip the write */