Commit cd32b27a authored by Yu Kuai's avatar Yu Kuai Committed by Song Liu
Browse files

md/dm-raid: don't call md_reap_sync_thread() directly 



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 130443d6 ("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: be83651f ("DM RAID: Add message/status support for changing sync action")
Cc: stable@vger.kernel.org # v6.7+
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarXiao Ni <xni@redhat.com>
Acked-by: default avatarMike Snitzer <snitzer@kernel.org>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240305072306.2562024-7-yukuai1@huaweicloud.com
parent 16c4770c

drivers/md/dm-raid.c

+18 −10
Original line number Diff line number Diff line
@@ -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;



		md_frozen_sync_thread(mddev);

		mddev_unlock(mddev);

	} else if (!strcasecmp(argv[0], "idle")) {

		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);

		md_idle_sync_thread(mddev);

		mddev_unlock(mddev);

	}

	} else if (decipher_sync_action(mddev, mddev->recovery) != st_idle)



	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 */