From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:33000 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932999AbdK1Kpz (ORCPT ); Tue, 28 Nov 2017 05:45:55 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiao Ni , NeilBrown , Shaohua Li Subject: [PATCH 4.14 076/193] md: fix deadlock error in recent patch. Date: Tue, 28 Nov 2017 11:25:23 +0100 Message-Id: <20171128100616.941099185@linuxfoundation.org> In-Reply-To: <20171128100613.638270407@linuxfoundation.org> References: <20171128100613.638270407@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit d47c8ad261f787af22a220ffcc2d07afba809223 upstream. A recent patch aimed to cause md_write_start() to fail (rather than block) when the mddev was suspending, so as to avoid deadlocks. Unfortunately the test in wait_event() was wrong, and it didn't change behaviour at all. We wait_event() must wait until the metadata is written OR the array is suspending. Fixes: cc27b0c78c79 ("md: fix deadlock between mddev_suspend() and md_write_start()") Reported-by: Xiao Ni Signed-off-by: NeilBrown Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman --- drivers/md/md.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8039,7 +8039,8 @@ bool md_write_start(struct mddev *mddev, if (did_change) sysfs_notify_dirent_safe(mddev->sysfs_state); wait_event(mddev->sb_wait, - !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) && !mddev->suspended); + !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags) || + mddev->suspended); if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags)) { percpu_ref_put(&mddev->writes_pending); return false;