cfgutils route_if_exists causing leak

[jchavanton]

Description

cfgutils route_if_exists can leak when
1: using a $var or $avp
2: some functions are called within the called route

Troubleshooting

Reproduction

reproduced on both Kamailio 4.4.x and 5.x

Note that in my tests the route is executed from rtimer in case this is part of the problem somehow.

modparam("rtimer", "timer", "name=tmetrics;interval=9;mode=1;")
modparam("rtimer", "exec", "timer=tmetrics;route=test")

example :

route[dummy] {
        xinfo("[dummy]");
        statsd_gauge("dummy_1xx", $stat(1xx_replies));
}
route[test] {
        $var(route_name) = "dummy";
        route_if_exists($var(route_name));
]

working alternative

route[dummy] {
        xinfo("[dummy]");
        statsd_gauge("dummy_1xx", $stat(1xx_replies));
}
route[test] {
        $var(route_name) = "dummy";
        if (check_route_exists($var(route_name))) {
                     route($var(route_name));
       } 
}

Debugging Data

kamcmd pkg.stats you can see the `real_used` of the timer process with leak every time the route is called

reproduced on both Kamailio 4.4.x and 5.x

[jchavanton]

Not sure if I will be able to find time for this one soon, since there is a working alternative this is probably low priority.

[miconda]

It's rather impossible that $var(...) is leaking, but be aware that its value persists across executions of route blocks, the value is reset only by a new assign.

Then $avp() is using shared memory, so not related to pkg.stats output.

I looked at the code for route_if_exists and I discovered that was executing the route block as a top route, not as a sub-route (what route(x) does). I pushed a patch for it. Maybe that was the cause of leak, eventually inside the statsd operation, because route_if_exists doesn't allocate anything itself.

Update: statsd seems also ok, after a quick look, so it might be something else, anyhow, maybe you can test with the patch referenced above and see if ok now.

[jchavanton]

right, it must be a side effect of having a variable param

kamcmd ps | grep met
2453	RTIMER EXEC child=0 timer=tmetrics
kamcmd pkg.stats | grep -A 5 2453 | grep real
	real_used: 2243864
kamcmd pkg.stats | grep -A 5 2453 | grep real
	real_used: 2244552

no luck with the patch ...

[miconda]

I pushed the above patch to have a similar behaviour for route_if_exists() like for route(). If the issue still exists, maybe it is better to open a new issue to track it in the context of the latest code.