Linux XDP client multi connection issues

[ami-GS]

Describe the bug

When client secnetperf running with multi connection using XDP, some packets arrive at normal socket datapath and hit segfault.

Client hits here
https://github.com/microsoft/msquic/pull/4551/files/e2a3ad4c123cec85f648841d61a9eeceba49778d#r1768132268

Affected OS

• Windows
• Linux
• macOS
• Other (specify below)

Additional OS information

Ubuntu 24.04

MsQuic version

main

Steps taken to reproduce bug

2 Ubuntu 24.04 VMs on Hyper-V on same Azure host (nested VM)

server
./artifacts/bin/linux/x64_Debug_openssl3/secnetperf -exec:maxtput -io:epoll -pollidle:1000

client
./artifacts/bin/linux/x64_Debug_openssl3/secnetperf -target:$TARGET_IP -exec:maxtput -down:10s -ptput:1 -tcp:0 -trimout -watchdog:25000 -pconn:1 -pstream:1 -io:xdp -conns:100

Expected behavior

continue running until the workload ends.

Actual outcome

use epoll datapath and segfault

Additional details

When running with multi-connection, some packets arrive at normal socket datapath for some reason even though all packets are forcibly routed to AF_XDP socket by hack.

hypothesis

• the packets arrive at normal datapath are mixed with the ones arrive at AF_XDP socket, then break code.
• netvsc has bug?
• host layer bug?
• nested VM bug?