Note that md_wakeup_thread_directly is racy - it will do nothing if the
thread is already running or it may cause spurious wake-up if the thread
is blocked in another subsystem.
In order to eliminate the race condition, we will retry
md_wakeup_thread_directly after 0.1 seconds.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v6.7
Fixes: 130443d60b1b ("md: refactor idle/frozen_sync_thread() to fix deadlock")
---
drivers/md/md.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
Index: linux-2.6/drivers/md/md.c
===================================================================
--- linux-2.6.orig/drivers/md/md.c
+++ linux-2.6/drivers/md/md.c
@@ -4889,6 +4889,7 @@ static void stop_sync_thread(struct mdde
mddev_unlock(mddev);
+retry:
set_bit(MD_RECOVERY_INTR, &mddev->recovery);
/*
* Thread might be blocked waiting for metadata update which will now
@@ -4898,9 +4899,11 @@ static void stop_sync_thread(struct mdde
if (work_pending(&mddev->sync_work))
flush_work(&mddev->sync_work);
- wait_event(resync_wait,
+ if (!wait_event_timeout(resync_wait,
!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
- (check_seq && sync_seq != atomic_read(&mddev->sync_seq)));
+ (check_seq && sync_seq != atomic_read(&mddev->sync_seq)),
+ HZ / 10))
+ goto retry;
if (locked)
mddev_lock_nointr(mddev);
