From 9e1b0211c5dd4acbd21a8ec1b86fc38a497a4656 Mon Sep 17 00:00:00 2001
From: Guoqing Jiang <gqjiang@suse.com>
Date: Mon, 25 Sep 2017 15:47:50 +0800
Subject: [PATCH 19/19] dlm: recheck kthread_should_stop() before schedule()
Git-commit: 9e1b0211c5dd4acbd21a8ec1b86fc38a497a4656
Patch-mainline: v4.15-rc1
References: bsc#1071422
Call schedule() here could make the thread miss wake
up from kthread_stop(), so it is better to recheck
kthread_should_stop() before call schedule(), a symptom
happened when I run indefinite test (which mostly created
clustered raid1, assemble it in other nodes, then stop
them) of clustered raid.
$ ps aux|grep md|grep D
root 4211 0.0 0.0 19760 2220 ? Ds 02:58 0:00 mdadm -Ssq
$ cat /proc/4211/stack
kthread_stop+0x4d/0x150
dlm_recoverd_stop+0x15/0x20 [dlm]
dlm_release_lockspace+0x2ab/0x460 [dlm]
leave+0xbf/0x150 [md_cluster]
md_cluster_stop+0x18/0x30 [md_mod]
bitmap_free+0x12e/0x140 [md_mod]
bitmap_destroy+0x7f/0x90 [md_mod]
__md_stop+0x21/0xa0 [md_mod]
do_md_stop+0x15f/0x5c0 [md_mod]
md_ioctl+0xa65/0x18a0 [md_mod]
blkdev_ioctl+0x49e/0x8d0
block_ioctl+0x41/0x50
do_vfs_ioctl+0x96/0x5b0
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x1e/0xad
This maybe not resolve the issue completely since the
KTHREAD_SHOULD_STOP flag could be set between "break"
and "schedule", but at least the chance for the symptom
happen could be reduce a lot (The indefinite test runs
more than 20 hours without problem and it happens easily
without the change).
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Gang He <ghe@suse.com>
---
fs/dlm/recoverd.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index d2ad1ca..6f4e1d4 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -299,8 +299,11 @@ static int dlm_recoverd(void *arg)
break;
}
if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
- !test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags))
+ !test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
+ if (kthread_should_stop())
+ break;
schedule();
+ }
set_current_state(TASK_RUNNING);
if (test_and_clear_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
--
1.8.5.6