Re: [syzbot] [mptcp?] KMSAN: uninit-value in mptcp_established_options

[Paolo Abeni]

On 5/29/26 4:41 AM, Matthieu Baerts wrote:
> On 08/05/2026 19:27, Paolo Abeni wrote:
>> On 5/7/26 9:44 AM, Matthieu Baerts wrote:
>>> Hi Paolo, Kuniyuki,
>>>
>>> On 04/05/2026 20:20, syzbot wrote:
>>>> Hello,
>>>>
>>>> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
>>>> KMSAN: uninit-value in irqentry_exit_to_kernel_mode_preempt
>>>
>>> It looks like the issue is different now:
> 
> (...)
> 
>>> Plus I'm not exactly sure to understand the issue here: mp_opt is
>>> defined and used only in mptcp_incoming_options(), and I don't see
>>> anything using it after the end of this function. Or did I miss something?
>>
>> I also had hard time understanding the backtrace, I think some frames
>> are omitted/missing (it happens sometime, IDK why), specifically the one
>> related to mptcp_options_received() - which would be useful to
>> understand the issue.
> 
> Because the other issue spot by syzbot seems to unrelated, do you plan
> to send your patch upstream? Or do you prefer if someone else does it?

I'm sorry /me is losing track of multiple items. I can send a formal
patch to the mptcp ML for:

https://lore.kernel.org/all/5841afcc-13ea-4bee-8645-634a02e76c4f@xxxxxxxxxx/#t

/P