[SR-Users] Using lock() correctly

Hi, for a project I need to make sure, I have a setup where I get mirror-traffic into Kamailio which has to do something with it. To work correctly, I need to make sure, the initial INVITE is processed correctly before any reply to the same call. So I thought I use lock() and unlock() for it. This is what the relevant kamailio.cfg part looks like: request_route { xlog("L_INFO", "Got new packet $rm: $si => $Ri\n"); route(li); } onreply_route { xlog("L_INFO", "Got new packet $rm: $si => $Ri - Reply Code $rs\n"); route(li); } route[magic] { lock("$ci"); xlog("L_INFO", "Obtained lock, calling lua...\n"); if(!lua_run("handle_packet")) { xlog("L_ERR", "SCRIPT: failed to execute lua function!\n"); } unlock("$ci"); xlog("L_INFO", "Lua finished, released lock...\n"); drop; exit; } And this is what the log says: Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: <script>: Got new packet INVITE: 172.20.21.247 => 172.20.21.4 Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: <script>: Obtained lock, calling lua... Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: app_lua [app_lua_sr.c:98]: lua_sr_log(): some logging Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>: Got new packet INVITE: 172.20.21.4 => 172.20.21.247 - Reply Code 407 Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>: Obtained lock, calling lua... Jun 28 13:27:04 busch /usr/sbin/kamailio[18837]: INFO: <script>: Lua finished, released lock... Jun 28 13:27:04 busch /usr/sbin/kamailio[18836]: INFO: app_lua [app_lua_sr.c:98]: lua_sr_log(): some more logging As far as I understand the documentation, the second packet should wait for the lock on the Call-ID before executing the lua function. So process 18836 should finish its lua execution before 18837 can do anything further. Did I completely misunderstand the lock() function? I'm using Kamailio 5.0.2. Thanks for helping me understand what Kamailio is doing here. Best Regards, Sebastian