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
