Re: [PATCH 00/12] Use connect()ed sockets for both sides of UDP flows

On Fri, Apr 25, 2025 at 08:27:00AM +0200, Stefano Brivio wrote:

On Fri, 4 Apr 2025 21:15:30 +1100 David Gibson wrote:

...

As discussed, I've been working on using connect()ed sockets, rather than dups of the listening sockets for handling traffic on the initiating side of UDP flows. This improves consistency, avoids some problems (bug 103) and will allow for some useful future improvements.

It has the nice side effect of allowing some more code to be shared between various paths, resulting in a pretty nice negative diffstat.

David Gibson (12): udp: Use connect()ed sockets for initiating side udp: Make udp_sock_recv() take max number of frames as a parameter udp: Polish udp_vu_sock_info() and remove from vu specific code udp: Don't bother to batch datagrams from "listening" socket udp: Parameterize number of datagrams handled by udp_*_reply_sock_data() udp: Split spliced forwarding path from udp_buf_reply_sock_data() udp: Merge vhost-user and "buf" listening socket paths udp: Move UDP_MAX_FRAMES to udp.c udp_flow: Take pif and port as explicit parameters to udp_flow_from_sock() udp: Rework udp_listen_sock_data() into udp_sock_fwd() udp: Fold udp_splice_prepare and udp_splice_send into udp_sock_to_sock udp_flow: Don't discard packets that arrive between bind() and connect()

Just for the record: it's likely that something here made https://github.com/containers/podman/issues/25959 more visible (or directly caused it). I couldn't rule out recent ICMP changes yet, but I'm fairly sure it's not those.

Drat. I concur this series is the likely culprit. First place to check would be the error paths for a flow initiated from the host side (there are new ones because this now involves opening a new socket). Maybe we didn't clean something up in one of those cases leaving a bomb for a future allocation. -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson