From: Chunguang Xu <brookxu@xxxxxxxxxxx> commit cca415537244f6102cbb09b5b90db6ae2c953bdd upstream. When freeing metadata, we will create an ext4_free_data and insert it into the pending free list. After the current transaction is committed, the object will be freed. ext4_mb_free_metadata() will check whether the area to be freed overlaps with the pending free list. If true, return directly. At this time, ext4_free_data is leaked. Fortunately, the probability of this problem is small, since it only occurs if the file system is corrupted such that a block is claimed by more one inode and those inodes are deleted within a single jbd2 transaction. Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx> Link: https://lore.kernel.org/r/1604764698-4269-8-git-send-email-brookxu@xxxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Cc: stable@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/ext4/mballoc.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4646,6 +4646,7 @@ ext4_mb_free_metadata(handle_t *handle, ext4_group_first_block_no(sb, group) + EXT4_C2B(sbi, cluster), "Block already on to-be-freed list"); + kmem_cache_free(ext4_free_data_cachep, new_entry); return 0; } }
