Re: [syzbot] [mptcp?] WARNING in __mptcp_move_skbs_from_subflow (2)

[Matthieu Baerts]

Hello,

-cc netdev & maintainers

On 21/11/2025 13:11, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    fd95357fd8c6 Merge tag 'sched_ext-for-6.18-rc6-fixes-2' of..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17220e92580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=1cd7f786c0f5182f
> dashboard link: https://syzkaller.appspot.com/bug?extid=9475dcc0b42355ded022
> compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: i386
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-fd95357f.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/9301ea2e80a9/vmlinux-fd95357f.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/13592a9d2a74/bzImage-fd95357f.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+9475dcc0b42355ded022@xxxxxxxxxxxxxxxxxxxxxxxxx

This bug has not been seen for quite a while, and we didn't find
anything wrong when looking at the related code. We then think it was
induced by a previous memory corruption. It can be re-opened if needed.

#syz invalid

Ref on our side:

  https://github.com/multipath-tcp/mptcp_net-next/issues/608

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.