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From: Miklos Szeredi <miklos@szeredi.hu>
Date: Fri, 17 May 2024 17:40:47 +0200
Message-ID: <CAJfpegtwuOgundfkCdh4c4-scJjBEgHjNzJ8Vq2VUxjxWWQPHQ@mail.gmail.com>
Subject: Re: [syzbot] [overlayfs?] WARNING in ovl_workdir_create (3)
To: syzbot <syzbot+8aa3f99a6acb9f8fd429@syzkaller.appspotmail.com>
Cc: amir73il@gmail.com, linux-kernel@vger.kernel.org, 
	linux-unionfs@vger.kernel.org, syzkaller-bugs@googlegroups.com
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On Mon, 13 May 2024 at 20:28, syzbot
<syzbot+8aa3f99a6acb9f8fd429@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    45db3ab70092 Merge tag '6.9-rc7-ksmbd-fixes' of git://git...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=169b934c980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=2f7a2b43b9e58995
> dashboard link: https://syzkaller.appspot.com/bug?extid=8aa3f99a6acb9f8fd429
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/0c2a8034002c/disk-45db3ab7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/807e35e2b3a9/vmlinux-45db3ab7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/4868b2eab91a/bzImage-45db3ab7.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+8aa3f99a6acb9f8fd429@syzkaller.appspotmail.com
>
> ------------[ cut here ]------------
> DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff888077f311f0, owner = 0x0, curr 0xffff8880787ebc00, list empty

This is lock corruption on the upper filesystem, definitely not an
overlayfs issue.

#syz unset subsystems

Thanks,
Miklos