From: Theodore Ts'o tytso@mit.edu
[ Upstream commit 3918e0667bbac99400b44fa5aef3f8be2eeada4a ]
[ 3934.173244] ====================================================== [ 3934.179572] WARNING: possible circular locking dependency detected [ 3934.185884] 5.4.21-xfstests #1 Not tainted [ 3934.190151] ------------------------------------------------------ [ 3934.196673] dmsetup/8897 is trying to acquire lock: [ 3934.201688] ffffffffbce82b18 (shrinker_rwsem){++++}, at: unregister_shrinker+0x22/0x80 [ 3934.210268] but task is already holding lock: [ 3934.216489] ffff92a10cc5e1d0 (&pmd->root_lock){++++}, at: dm_pool_metadata_close+0xba/0x120 [ 3934.225083] which lock already depends on the new lock.
[ 3934.564165] Chain exists of: shrinker_rwsem --> &journal->j_checkpoint_mutex --> &pmd->root_lock
For a more detailed lockdep report, please see:
https://lore.kernel.org/r/20200220234519.GA620489@mit.edu
We shouldn't need to hold the lock while are just tearing down and freeing the whole metadata pool structure.
Fixes: 44d8ebf436399a4 ("dm thin metadata: use pool locking at end of dm_pool_metadata_close") Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/dm-thin-metadata.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 8bb723f1a569a..4cd8868f80040 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -960,9 +960,9 @@ int dm_pool_metadata_close(struct dm_pool_metadata *pmd) DMWARN("%s: __commit_transaction() failed, error = %d", __func__, r); } + pmd_write_unlock(pmd); if (!pmd->fail_io) __destroy_persistent_data_objects(pmd); - pmd_write_unlock(pmd);
kfree(pmd); return 0;