October 28, 2025 at 19:47, "Paolo Abeni" <[email protected] mailto:[email protected]?to=%22Paolo%20Abeni%22%20%3Cpabeni%40redhat.com%3E > wrote:
> > On 10/28/25 12:30 PM, Paolo Abeni wrote: > > > > > On 10/23/25 2:54 PM, Jiayuan Chen wrote: > > > > > > > > When the server has MPTCP enabled but receives a non-MP-capable request > > > from a client, it calls mptcp_fallback_tcp_ops(). > > > > > > Since non-MPTCP connections are allowed to use sockmap, which replaces > > > sk->sk_prot, using sk->sk_prot to determine the IP version in > > > mptcp_fallback_tcp_ops() becomes unreliable. This can lead to assigning > > > incorrect ops to sk->sk_socket->ops. > > > > > > > I don't see how sockmap could modify the to-be-accepted socket sk_prot > > before mptcp_fallback_tcp_ops(), as such call happens before the fd is > > installed, and AFAICS sockmap can only fetch sockets via fds. > > > > Is this patch needed? > > > Matttbe explained off-list the details of how that could happen. I think > the commit message here must be more verbose to explain clearly the > whys, even to those non proficient in sockmap like me. > > Thanks, > > Paolo > Thanks, I will add more details into commit message :).
