syzbot report slab-out-of-bounds in journal_entry_dev_usage_to_text,
it because vstruct_bytes(entry) smaller than sizeof(struct 
jset_entry_dev_usage), overflow occurs when calculating the difference in
jset_entry_dev_usage_nr_types(u).

Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=05d7520be047c9be86e0
Signed-off-by: Edward Adam Davis <[email protected]>
---
 fs/bcachefs/sb-clean.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/bcachefs/sb-clean.c b/fs/bcachefs/sb-clean.c
index 47f10ab57f40..278e1a25159a 100644
--- a/fs/bcachefs/sb-clean.c
+++ b/fs/bcachefs/sb-clean.c
@@ -310,6 +310,9 @@ static void bch2_sb_clean_to_text(struct printbuf *out, 
struct bch_sb *sb,
                    !entry->u64s)
                        continue;
 
+               if (vstruct_bytes(entry) < sizeof(struct jset_entry_dev_usage))
+                       continue;
+
                bch2_journal_entry_to_text(out, NULL, entry);
                prt_newline(out);
        }
-- 
2.43.0


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