Re: [syzbot] [overlayfs?] KASAN: invalid-free in ovl_copy_up_one

[Jann Horn]

On Wed, Sep 27, 2023 at 5:10 PM syzbot
<syzbot+477d8d8901756d1cbba1@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
>
> Reported-and-tested-by: syzbot+477d8d8901756d1cbba1@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> Tested on:
>
> commit:         8e9b46c4 ovl: do not encode lower fh with upper sb_wri..
> git tree:       https://github.com/amir73il/linux.git ovl_want_write
> console output: https://syzkaller.appspot.com/x/log.txt?x=10d10ffa680000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=bb54ecdfa197f132
> dashboard link: https://syzkaller.appspot.com/bug?extid=477d8d8901756d1cbba1
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

It looks like the fix was submitted without the Reported-by tag, so
syzkaller doesn't recognize that the fix has landed... I'll tell
syzkaller now which commit the fix is supposed to be in, please
correct me if this is wrong:

#syz fix: ovl: do not encode lower fh with upper sb_writers held