Re: [ext4?] [ocfs2?] WARNING in jbd2_journal_update_sb_log_tail

[Lizhi Xu]

The s_sequence value of journal superblock loaded from disk is 4294967295,
is it too large?

#syz test

diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 97f487c3d8fc..563c4af533ac 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1397,6 +1397,12 @@ static int journal_check_superblock(journal_t *journal)
 		}
 	}
 
+	if (sb->s_sequence == U32_MAX) {
+		pr_err("JBD2: Load a too big s_sequence: %u, %s\n", 
+			sb->s_sequence, __func__);
+		return err;
+	}
+
 	return 0;
 }