diff options
| author | NeilBrown | 2017-08-08 16:56:36 +1000 |
|---|---|---|
| committer | Shaohua Li | 2017-08-08 07:42:35 -0700 |
| commit | 33182d15c6bf182f7ae32a66ea4a547d979cd6d7 (patch) | |
| tree | 3474674380ae8c826eb5f19d36da994464535345 /drivers/md | |
| parent | 16f73eb02d7e1765ccab3d2018e0bd98eb93d973 (diff) | |
md: always clear ->safemode when md_check_recovery gets the mddev lock.
If ->safemode == 1, md_check_recovery() will try to get the mddev lock
and perform various other checks.
If mddev->in_sync is zero, it will call set_in_sync, and clear
->safemode. However if mddev->in_sync is not zero, ->safemode will not
be cleared.
When md_check_recovery() drops the mddev lock, the thread is woken
up again. Normally it would just check if there was anything else to
do, find nothing, and go to sleep. However as ->safemode was not
cleared, it will take the mddev lock again, then wake itself up
when unlocking.
This results in an infinite loop, repeatedly calling
md_check_recovery(), which RCU or the soft-lockup detector
will eventually complain about.
Prior to commit 4ad23a976413 ("MD: use per-cpu counter for
writes_pending"), safemode would only be set to one when the
writes_pending counter reached zero, and would be cleared again
when writes_pending is incremented. Since that patch, safemode
is set more freely, but is not reliably cleared.
So in md_check_recovery() clear ->safemode before checking ->in_sync.
Fixes: 4ad23a976413 ("MD: use per-cpu counter for writes_pending")
Cc: stable@vger.kernel.org (4.12+)
Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reported-by: David R <david@unsolicited.net>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/md.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index c99634612fc4..d84aceede1cb 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8656,6 +8656,9 @@ void md_check_recovery(struct mddev *mddev) if (mddev_trylock(mddev)) { int spares = 0; + if (mddev->safemode == 1) + mddev->safemode = 0; + if (mddev->ro) { struct md_rdev *rdev; if (!mddev->external && mddev->in_sync) |