From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57136 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751486AbdJBMap (ORCPT ); Mon, 2 Oct 2017 08:30:45 -0400 Subject: Patch "md: fix a race condition for flush request handling" has been added to the 4.13-stable tree To: shli@fb.com, gregkh@linuxfoundation.org, nate.dailey@stratus.com, neilb@suse.com Cc: , From: Date: Mon, 02 Oct 2017 14:30:12 +0200 Message-ID: <1506947412189215@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled md: fix a race condition for flush request handling to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: md-fix-a-race-condition-for-flush-request-handling.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 79bf31a3b2a7ca467cfec8ff97d359a77065d01f Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 21 Sep 2017 09:55:28 -0700 Subject: md: fix a race condition for flush request handling From: Shaohua Li commit 79bf31a3b2a7ca467cfec8ff97d359a77065d01f upstream. md_submit_flush_data calls pers->make_request, which missed the suspend check. Fix it with the new md_handle_request API. Reported-by: Nate Dailey Tested-by: Nate Dailey Fix: cc27b0c78c79(md: fix deadlock between mddev_suspend() and md_write_start()) Reviewed-by: NeilBrown Signed-off-by: Shaohua Li Signed-off-by: Greg Kroah-Hartman --- drivers/md/md.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -439,16 +439,22 @@ static void md_submit_flush_data(struct struct mddev *mddev = container_of(ws, struct mddev, flush_work); struct bio *bio = mddev->flush_bio; + /* + * must reset flush_bio before calling into md_handle_request to avoid a + * deadlock, because other bios passed md_handle_request suspend check + * could wait for this and below md_handle_request could wait for those + * bios because of suspend check + */ + mddev->flush_bio = NULL; + wake_up(&mddev->sb_wait); + if (bio->bi_iter.bi_size == 0) /* an empty barrier - all done */ bio_endio(bio); else { bio->bi_opf &= ~REQ_PREFLUSH; - mddev->pers->make_request(mddev, bio); + md_handle_request(mddev, bio); } - - mddev->flush_bio = NULL; - wake_up(&mddev->sb_wait); } void md_flush_request(struct mddev *mddev, struct bio *bio) Patches currently in stable-queue which might be from shli@fb.com are queue-4.13/md-separate-request-handling.patch queue-4.13/md-raid5-preserve-stripe_on_unplug_list-in-break_stripe_batch_list.patch queue-4.13/md-fix-a-race-condition-for-flush-request-handling.patch queue-4.13/md-raid5-fix-a-race-condition-in-stripe-batch.patch