Re: [PATCH v7 23/27] udp: Find or create flows for datagrams from tap interface

[Stefano Brivio <sbrivio@redhat.com>]

Some nits in the commit message only:

On Fri,  5 Jul 2024 12:07:20 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> Currently we create flows for datagrams from socket interfaces, and use
> them to direct "spliced" (socket to socket) datagrams.  We don't yet
> match datagrams from the tap interface to existing flows, nor create new
> flows for them.  Add that functionality, matching datagrams from tap to
> existing flows when they exist, or creating new ones.
> 
> As with spliced flows, when creating a new flow from tap to socket, we
> create a new connected socket to receive reply datagrams attached to that
> flow specifically. We extend udp_flow_sock_handler() to handle reply
> packets bound for tap rather than another socket.
> 
> For non-obvious reasons, this caused a failure for me when running under
> valgrind, because valgrind invoked rt_sigreturn which is not in our
> seccomp filter.

That might be because the stack area needed by udp_reply_sock_handler()
is now a bit bigger... or something like that, I suppose.

> Since we already allow rt_signaction and others in the

rt_sigaction

> valgrind, it seems reasonable to add rt_sigreturn as well.

valgrind target

-- 
Stefano