Messages in this thread Patch in this message | | | From | Mikhail Ukhin <> | Subject | [PATCH] ext4: fix semaphore unlocking order | Date | Thu, 28 Mar 2024 17:33:01 +0300 |
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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.
Signed-off-by: Artem Sadovnikov <ancowi69@gmail.com> --- 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 d98ac2af8199..a5e1492bbaaa 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: ext4_writepages_up_write(inode->i_sb, alloc_ctx); return ret; -- 2.25.1
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