Re: [syzbot] [bcachefs?] kernel BUG in bch2_printbuf_exit

[Kent Overstreet]

On Thu, Jul 17, 2025 at 12:13:32PM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    e8352908bdcd Add linux-next specific files for 20250716
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=100e158c580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=2594af20939db736
> dashboard link: https://syzkaller.appspot.com/bug?extid=1faf405b707c6475482f
> compiler:       Debian clang version 20.1.7 
> (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17b1e382580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10e8e7d4580000

regression from the CLASS() conversion, fixed by:

commit e9b9bdc34894fb1cd5d0798507b4cca4f6435ad3
Author: Kent Overstreet <kent.overstr...@linux.dev>
Date:   Thu Jul 17 15:20:06 2025 -0400

    fixup! bcachefs: convert str_hash.c to CLASS

diff --git a/fs/bcachefs/str_hash.c b/fs/bcachefs/str_hash.c
index dfe4b6ae0733..3e08e55d2dc1 100644
--- a/fs/bcachefs/str_hash.c
+++ b/fs/bcachefs/str_hash.c
@@ -329,7 +329,6 @@ int bch2_str_hash_repair_key(struct btree_trans *trans,
 out:
 fsck_err:
        bch2_trans_iter_exit(trans, dup_iter);
-       printbuf_exit(&buf);
        if (free_snapshots_seen)
                darray_exit(&s->ids);
        return ret;