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authorGuoqing Jiang <gqjiang@suse.com>2017-10-09 10:32:48 +0800
committerShaohua Li <shli@fb.com>2017-10-08 20:36:39 -0700
commitd1d90147c9680aaec4a5757932c2103c42c9c23b (patch)
tree20986021b290c8c30375b90020a5c7bf51de4fc5 /drivers/md
parentd47c8ad261f787af22a220ffcc2d07afba809223 (diff)
md: always set THREAD_WAKEUP and wake up wqueue if thread existed
Since commit 4ad23a976413 ("MD: use per-cpu counter for writes_pending"), the wait_queue is only got invoked if THREAD_WAKEUP is not set previously. With above change, I can see process_metadata_update could always hang on the wait queue, because mddev->thread could stay on 'D' status and the THREAD_WAKEUP flag is not cleared since there are lots of place to wake up mddev->thread. Then deadlock happened as follows: linux175:~ # ps aux|grep md|grep D root 20117 0.0 0.0 0 0 ? D 03:45 0:00 [md0_raid1] root 20125 0.0 0.0 0 0 ? D 03:45 0:00 [md0_cluster_rec] linux175:~ # cat /proc/20117/stack [<ffffffffa0635604>] dlm_lock_sync+0x94/0xd0 [md_cluster] [<ffffffffa0635674>] lock_token+0x34/0xd0 [md_cluster] [<ffffffffa0635804>] metadata_update_start+0x64/0x110 [md_cluster] [<ffffffffa04d985b>] md_update_sb.part.58+0x9b/0x860 [md_mod] [<ffffffffa04da035>] md_update_sb+0x15/0x30 [md_mod] [<ffffffffa04dc066>] md_check_recovery+0x266/0x490 [md_mod] [<ffffffffa06450e2>] raid1d+0x42/0x810 [raid1] [<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod] [<ffffffff81091741>] kthread+0x101/0x140 linux175:~ # cat /proc/20125/stack [<ffffffffa0636679>] recv_daemon+0x3f9/0x5c0 [md_cluster] [<ffffffffa04d2252>] md_thread+0x122/0x150 [md_mod] [<ffffffff81091741>] kthread+0x101/0x140 So let's revert the part of code in the commit to resovle the problem since we can't get lots of benefits of previous change. Fixes: 4ad23a976413 ("MD: use per-cpu counter for writes_pending") Signed-off-by: Guoqing Jiang <gqjiang@suse.com> Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/md.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 8b2eb0f4122f..707471e3cb01 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7468,8 +7468,8 @@ void md_wakeup_thread(struct md_thread *thread)
{
if (thread) {
pr_debug("md: waking up MD thread %s.\n", thread->tsk->comm);
- if (!test_and_set_bit(THREAD_WAKEUP, &thread->flags))
- wake_up(&thread->wqueue);
+ set_bit(THREAD_WAKEUP, &thread->flags);
+ wake_up(&thread->wqueue);
}
}
EXPORT_SYMBOL(md_wakeup_thread);