netdev - Re: [PATCH net-next 2/3] tcp: add newval parameter to tcp_rcvbuf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <b6964938358dc1af41c9fefda071c19e81c8e64a.camel@kernel.org>
Date: Mon, 27 Oct 2025 14:17:21 +0800
From: Geliang Tang <geliang@...nel.org>
To: Matthieu Baerts <matttbe@...nel.org>, Eric Dumazet
 <edumazet@...gle.com>,  Paolo Abeni <pabeni@...hat.com>
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski
 <kuba@...nel.org>,  Simon Horman <horms@...nel.org>, Neal Cardwell
 <ncardwell@...gle.com>, Willem de Bruijn <willemb@...gle.com>,  Kuniyuki
 Iwashima <kuniyu@...gle.com>, Mat Martineau <martineau@...nel.org>, 
 netdev@...r.kernel.org, eric.dumazet@...il.com
Subject: Re: [PATCH net-next 2/3] tcp: add newval parameter to
 tcp_rcvbuf_grow()

Hi Eric, Paolo, Matt,

On Fri, 2025-10-24 at 17:27 +0200, Matthieu Baerts wrote:
> On 24/10/2025 16:58, Eric Dumazet wrote:
> > On Fri, Oct 24, 2025 at 7:47 AM Eric Dumazet <edumazet@...gle.com>
> > wrote:
> > > 
> > 
> > > 
> > > I usually stack multiple patches, and net-next allows for less
> > > merge conflicts.
> > > 
> > > See for instance
> > > https://lore.kernel.org/netdev/20251024120707.3516550-1-edumazet@google.com/T/#u
> > > which touches tcp_rcv_space_adjust(), and definitely net-next
> > > candidate.
> > > 
> > > Bug was added 5 months ago, and does not seem critical to me
> > > (otherwise we would have caught it much much earlier) ?
> > > 
> > > Truth be told, I had first to fix TSO defer code, and thought the
> > > fix
> > > was not good enough.
> > 
> > To clarify, I will send the V2 targeting net tree, since you asked
> > for it ;)
> 
> Thank you very much!
> 
> Note that the bug was apparently more visible with MPTCP, but only
> since
> a few weeks ago, after the modifications on MPTCP side. When I looked
> at
> the issue, I didn't suspect anything wrong on the algorithm that was
> copied from TCP side, because this original code was there for a few
> months (and its author is very trustable :) ). So again, thank you
> for
> having fixed that!

I have just tested and confirmed that this series, together with
Paolo's correction (changing msk->rcvq_space.copied to msk-
>rcvq_space.space in mptcp_rcvbuf_grow()), fixes the simult_flows.sh
issue mentioned in [1].

Thanks,
-Geliang

[1]
https://github.com/multipath-tcp/mptcp_net-next/issues/589

> 
> Cheers,
> Matt