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

[Paolo Abeni]

On Wed, 2024-01-24 at 02:25 -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    6613476e225e Linux 6.8-rc1
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1200cf0de80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f9804db253bdfc61
> dashboard link: https://syzkaller.appspot.com/bug?extid=732ab7be796ec0d104ac
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=111fe2bfe80000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17abc23be80000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/cdad5c52fcde/disk-6613476e.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/14491fee3433/vmlinux-6613476e.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/953a5864daf4/bzImage-6613476e.xz
> 
> The issue was bisected to:
> 
> commit 14c56686a64c65ba716ff48f1f4b19c85f4cb2a9
> Author: Geliang Tang <geliang.tang@xxxxxxxx>
> Date:   Wed Oct 18 18:23:55 2023 +0000
> 
>     mptcp: avoid sending RST when closing the initial subflow
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=159a9427e80000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=179a9427e80000
> console output: https://syzkaller.appspot.com/x/log.txt?x=139a9427e80000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+732ab7be796ec0d104ac@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: 14c56686a64c ("mptcp: avoid sending RST when closing the initial subflow")

I forgot to mention this is looks like a legit mptcp-related issue.

There is a fix for this in the mptcp devel branch that should land here
somewhat soonish.

Cheers,

Paolo