diff mbox series

dm-raid: Fix WARN_ON_ONCE check for sync_thread in raid_resume

Message ID 20240611215528.846776-1-bmarzins@redhat.com (mailing list archive)
State Superseded, archived
Headers show
Series dm-raid: Fix WARN_ON_ONCE check for sync_thread in raid_resume | expand

Checks

Context Check Description
mdraidci/vmtest-md-6_11-PR success PR summary
mdraidci/vmtest-md-6_11-VM_Test-0 success Logs for build-kernel

Commit Message

Benjamin Marzinski June 11, 2024, 9:55 p.m. UTC
rm-raid devices will occasionally trigger the following warning when
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 <yukuai1@huaweicloud.com>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 drivers/md/dm-raid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Yu Kuai June 12, 2024, 1:25 a.m. UTC | #1
Hi,

在 2024/06/12 5:55, Benjamin Marzinski 写道:
> rm-raid devices will occasionally trigger the following warning when
> 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 <yukuai1@huaweicloud.com>
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> ---
>   drivers/md/dm-raid.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
> index abe88d1e6735..74184989fd15 100644
> --- a/drivers/md/dm-raid.c
> +++ b/drivers/md/dm-raid.c
> @@ -4102,7 +4102,7 @@ static void raid_resume(struct dm_target *ti)
>   			rs_set_capacity(rs);
>   
>   		WARN_ON_ONCE(!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery));
> -		WARN_ON_ONCE(test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
> +		WARN_ON_ONCE(mddev->sync_thread);

sync_thread is protected by rcu, I think this will cause spares warning.
Please use:

rcu_dereferenct_protected(mddev->sync_thread, 
lockdep_is_held(&mddev->reconfig_mutex));

Otherwise, LGTM.
Thanks

>   		clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
>   		mddev_lock_nointr(mddev);
>   		mddev->ro = 0;
>
diff mbox series

Patch

diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index abe88d1e6735..74184989fd15 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -4102,7 +4102,7 @@  static void raid_resume(struct dm_target *ti)
 			rs_set_capacity(rs);
 
 		WARN_ON_ONCE(!test_bit(MD_RECOVERY_FROZEN, &mddev->recovery));
-		WARN_ON_ONCE(test_bit(MD_RECOVERY_RUNNING, &mddev->recovery));
+		WARN_ON_ONCE(mddev->sync_thread);
 		clear_bit(RT_FLAG_RS_FROZEN, &rs->runtime_flags);
 		mddev_lock_nointr(mddev);
 		mddev->ro = 0;