From: Yu Kuai <yukuai3@xxxxxxxxxx>
Currently md_reap_sync_thread() is called from raid_message() directly
without holding 'reconfig_mutex', this is definitely unsafe because
md_reap_sync_thread() can change many fields that is protected by
'reconfig_mutex'.
However, hold 'reconfig_mutex' here is still problematic because this
will cause deadlock, for example, commit 130443d60b1b ("md: refactor
idle/frozen_sync_thread() to fix deadlock").
Fix this problem by using stop_sync_thread() to unregister sync_thread,
like md/raid did.
Fixes: be83651f0050 ("DM RAID: Add message/status support for changing sync action")
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/dm-raid.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 5ce3c6020b1b..6b6c011d9f69 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -3719,6 +3719,7 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
{
struct raid_set *rs = ti->private;
struct mddev *mddev = &rs->md;
+ int ret = 0;
if (!mddev->pers || !mddev->pers->sync_request)
return -EINVAL;
@@ -3726,17 +3727,24 @@ static int raid_message(struct dm_target *ti, unsigned int argc, char **argv,
if (test_bit(RT_FLAG_RS_SUSPENDED, &rs->runtime_flags))
return -EBUSY;
- if (!strcasecmp(argv[0], "frozen"))
- set_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
- else
- clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ if (!strcasecmp(argv[0], "frozen")) {
+ ret = mddev_lock(mddev);
+ if (ret)
+ return ret;
- if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], "frozen")) {
- if (mddev->sync_thread) {
- set_bit(MD_RECOVERY_INTR, &mddev->recovery);
- md_reap_sync_thread(mddev);
- }
- } else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
+ md_frozen_sync_thread(mddev);
+ mddev_unlock(mddev);
+ } else if (!strcasecmp(argv[0], "idle")) {
+ ret = mddev_lock(mddev);
+ if (ret)
+ return ret;
+
+ md_idle_sync_thread(mddev);
+ mddev_unlock(mddev);
+ }
+
+ clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+ if (decipher_sync_action(mddev, mddev->recovery) != st_idle)
return -EBUSY;
else if (!strcasecmp(argv[0], "resync"))
; /* MD_RECOVERY_NEEDED set below */
--
2.39.2
