This is a note to let you know that I've just added the patch titled md/raid5: add thread_group worker async_tx_issue_pending_all to the 4.4-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-raid5-add-thread_group-worker-async_tx_issue_pending_all.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 7e96d559634b73a8158ee99a7abece2eacec2668 Mon Sep 17 00:00:00 2001 From: Ofer Heifetz <oferh@xxxxxxxxxxx> Date: Mon, 24 Jul 2017 09:17:40 +0300 Subject: md/raid5: add thread_group worker async_tx_issue_pending_all From: Ofer Heifetz <oferh@xxxxxxxxxxx> commit 7e96d559634b73a8158ee99a7abece2eacec2668 upstream. Since thread_group worker and raid5d kthread are not in sync, if worker writes stripe before raid5d then requests will be waiting for issue_pendig. Issue observed when building raid5 with ext4, in some build runs jbd2 would get hung and requests were waiting in the HW engine waiting to be issued. Fix this by adding a call to async_tx_issue_pending_all in the raid5_do_work. Signed-off-by: Ofer Heifetz <oferh@xxxxxxxxxxx> Signed-off-by: Shaohua Li <shli@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/raid5.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5821,6 +5821,8 @@ static void raid5_do_work(struct work_st pr_debug("%d stripes handled\n", handled); spin_unlock_irq(&conf->device_lock); + + async_tx_issue_pending_all(); blk_finish_plug(&plug); pr_debug("--- raid5worker inactive\n"); Patches currently in stable-queue which might be from oferh@xxxxxxxxxxx are queue-4.4/md-raid5-add-thread_group-worker-async_tx_issue_pending_all.patch