Re: [PATCH v2] ext4: fix i_data_sem unlock order in ext4_ind_migrate()

On Sat, Apr 06, 2024 at 12:08:03AM +0300, Mikhail Ukhin wrote:

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

Thanks. This has been addressed by commit 00d873c17e29 ("ext4: avoid deadlock in fs reclaim with page writeback"), with the same code change.

- Ted