Re: [PATCH v2] dm-raid: Fix WARN_ON_ONCE check for sync_thread in raid_resume
From: Yu Kuai <hidden>
Date: 2024-06-13 03:50:57
Also in:
dm-devel
Hi, 在 2024/06/13 2:12, Benjamin Marzinski 写道:
rm-raid devices will occasionally trigger the following warning when
dm-raid
being resumed after a table load because DM_RECOVERY_RUNNING is set:
WARNING: CPU: 7 PID: 5660 at drivers/md/dm-raid.c:4105 raid_resume+0xee/0x100 [dm_raid]
The failing check is:
WARN_ON_ONCE(test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
This check is designed to make sure that the sync thread isn't
registered, but md_check_recovery can set MD_RECOVERY_RUNNING without
the sync_thread ever getting registered. Instead of checking if
MD_RECOVERY_RUNNING is set, check if sync_thread is non-NULL.
Fixes: 16c4770c75b1 ("dm-raid: really frozen sync_thread during suspend")
Suggested-by: Yu Kuai <redacted>Please use the address yukuai3@huawei.com
quoted hunk ↗ jump to hunk
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> --- Changes in v2: - Move mddev_lock_nointr() earlier to protect dereference and use rcu_dereference_protected() to access sync_thread drivers/md/dm-raid.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index abe88d1e6735..b149ac46a990 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c@@ -4101,10 +4101,11 @@ static void raid_resume(struct dm_target *ti) if (mddev->delta_disks < 0) rs_set_capacity(rs); + mddev_lock_nointr(mddev); WARN_ON_ONCE(!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery)); - WARN_ON_ONCE(test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)); + WARN_ON_ONCE(rcu_dereference_protected(mddev->sync_thread, + lockdep_is_held(&mddev->reconfig_mutex))); clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags); - mddev_lock_nointr(mddev);
Other than the typo, LGTM Suggested-and-reviewed-by: Yu Kuai [off-list ref]
mddev->ro = 0; mddev->in_sync = 0; md_unfrozen_sync_thread(mddev);