https://bugs.winehq.org/show_bug.cgi?id=54995
--- Comment #3 from Bernhard Übelacker bernhardu@mailbox.org --- It looks like I did not add the actual call to socket_list_find in the attachement ...
(rr) bt #0 socket_list_find () at ...dlls/ws2_32/socket.c:406 #1 WS2_sendto () at ...dlls/ws2_32/socket.c:1003 #2 WSASendTo () at ...dlls/ws2_32/socket.c:3093 #3 fhandler_socket_wsock::send_internal () at ...winsup/cygwin/fhandler/socket_inet.cc:1431 ...
To workaround this issue it might be already enough to remove the check from WS2_sendto. Hope that helps.