Fuzzing reports a possible deadlock in jbd2_log_wait_commit.

The problem occurs in ext4_ind_migrate due to an incorrect order of unlocking of the journal and write semaphores - the order of unlocking must be the reverse of the order of locking.

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Signed-off-by: Artem Sadovnikov ancowi69@gmail.com Signed-off-by: Mikhail Ukhin mish.uxin2012@yandex.ru --- v2: New addresses have been added and Ritesh Harjani has been noted as a reviewer. fs/ext4/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index b0ea646454ac..59290356aa5b 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -663,8 +663,8 @@ int ext4_ind_migrate(struct inode *inode) if (unlikely(ret2 && !ret)) ret = ret2; errout: - ext4_journal_stop(handle); up_write(&EXT4_I(inode)->i_data_sem); + ext4_journal_stop(handle); out_unlock: percpu_up_write(&sbi->s_writepages_rwsem); return ret;