[kamailio/kamailio] segfault on t_next_contacts after adding additional contacts to $xavp(tm_contacts) (Issue #4063) - sr-dev

11 Dec 2024

### Description

Goal: Build a destination set from multiple contacts gathered from multiple registered
AoR.

Situation: assumptions, observations:

* lookup() returns success there are registered contacts for each AoR.
* All contacts have same q value.
* lookup() can only be called for one AoR, there is no way to call it for multiple AoR.
* If lookup() is called multiple times, only the destination set gathered by the last
invocation is preserved, all other ones are overwritten.
* t_load_contacts() transfers the destination set into the $xavp(tm_contacts) but like
lookup() initializes that 

So I am trying to find a way to store/collate all destination sets into one and parallel
fork a call to all contacts from multiple AoR.

Idea: Stack all contacts in $xavp(contact_stack) with the same structure as
$xavp(tm_contacts) and append it to tm_contacts.

xavp_rm("contact_stack"); # Make sure this is not defined.
We are in a loop setting $var(lookupuri) to (sip:315996608@3cx-pbx.imp.ch and
sip:315996608-1@157.161.4.181) {

  lookup("location", "$var(lookupuri)");
  t_load_contacts(0); # Now $xavp(tm_contacts) is populated
  $xavp(contact_stack) = $xavp(tm_contacts); # Store contact set

}
xavp_rm("tm_contacts"); # Re Initialize tm_contacts to empty
$xavp(tm_contacts) = $xavp(contact_stack); # Restore tm_contacts from stacked set.

xlog("L_INFO", "$cfg(route): COUNT: $cnt($xavp(tm_contacts))\n"); #
Make sure, the count matches what we expect.
xlog("L_INFO", "$cfg(route): Before t_next_contacts\n");
t_next_contacts(); # Load destination set => CRASH!
xlog("L_INFO", "$cfg(route): After t_next_contacts\n");

Log (some more infos logged I omitted in the example above)

```
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Auth_aor_user[0] = 315996608 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Sigprofile[0] = local 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Lookupuri[0] = sip:315996608@3cx-pbx.imp.ch 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
LOOKUP sip:315996608@3cx-pbx.imp.ch SUCCESS!!!!
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Auth_aor_user[1] = 315996608-1 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Sigprofile[1] = local 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Lookupuri[1] = sip:315996608-1@157.161.4.181 
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
LOOKUP sip:315996608-1@157.161.4.181 SUCCESS!!!!
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION: ADD
to tm_contacts
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
COUNT: 4
Dec 10 16:18:05 dev-cpereg01 kamailio[3964710]: INFO: [1 0618269314
128182546-3942836285-478214563(a)prt-cbl-sbc1.imp.ch 2 INVITE]<script>: LOCATION:
Before t_next_contacts
Dec 10 16:18:05 dev-cpereg01 kernel: [13747450.274883] traps: kamailio[3964710] general
protection fault ip:55bc00e61f2b sp:7ffce62d7520 error:0 in kamailio[55bc00ba5000+457000]
```

#### Reproduction

Code above with: version: kamailio 5.7.6 (x86_64/linux) from official kamailio repository
on ubuntu jammy.

#### Debugging Data

If required, I can try to enable coredumps.

#### Log Messages

Shown above

#### SIP Traffic

Probably not needed.

### Possible Solutions

None yet.

-- 
Reply to this email directly or view it on GitHub:
https://github.com/kamailio/kamailio/issues/4063
You are receiving this because you are subscribed to this thread.

Message ID: &lt;kamailio/kamailio/issues/4063(a)github.com&gt;