stuck in high CPU usage mod_lua

[jchavanton]

Describe the bug
Once in a while, running FS instances can get stuck in high CPU usage.

To Reproduce
Intermittent, not clear.

Expected behavior
A few threads are starting to use 100% CPU

Package version or git hash

• Version [master]

GDB attach

top -H -p 1

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                                                                                             
      1 root      -2 -10 4461968 465116  40592 S  99.9   2.9     3w+0d freeswitch                                                                                                                          
    181 root      -2 -10 4461968 465116  40592 R  98.0   2.9    6d+19h freeswitch                                                                                                                          
    182 root      -2 -10 4461968 465116  40592 R  95.0   2.9    6d+18h freeswitch                                                                                                                          
   1612 root      -2 -10 4461968 465116  40592 R  95.0   2.9    6d+16h freeswitch                                                                                                                          

gdb /usr/local/freeswitch/bin/freeswitch 1

(gdb) symbol-file /usr/local/freeswitch/bin/freeswitch
(gdb) info threads

  39   Thread 0x7f941f4586c0 (LWP 181) "freeswitch"  SWIG_PropagateClientData () at mod_lua_wrap.cpp:10711
  40   Thread 0x7f941f41b6c0 (LWP 182) "freeswitch"  0x00007f941fd3fb9d in SWIG_PropagateClientData () at mod_lua_wrap.cpp:10711
  41   Thread 0x7f941d1146c0 (LWP 1612) "freeswitch" 0x00007f949c8f315f in __GI___poll (fds=fds@entry=0x7f941d10a800, nfds=1, timeout=timeout@entry=20) at ../sysdeps/unix/sysv/linux/poll.c:29

Related Commit

commit 830a8493deff2bc2571023fad899c31fd2edab32
Author: Anthony Minessale <[email protected]>
Date:   Mon Jun 2 23:37:12 2008 +0000

    add answered and mediaReady methods to CoreSession
    
    git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@8743 d0543943-73ff-0310-b7d9-9358b9ac24b2

I can see the endless loop

(gdb) p *equiv
$2 = {type = 0x7f941fd4da20, converter = 0x0, next = 0x7f941fd4d120, prev = 0x7f941fd4d120}

  for (i = 0; i < swig_module.size; i++) {
    if (swig_module.types[i]->clientdata) {
      equiv = swig_module.types[i]->cast;
      while (equiv) {
        if (!equiv->converter) {
          if (equiv->type && !equiv->type->clientdata)                                                                                                                                                     
            SWIG_TypeClientData(equiv->type, swig_module.types[i]->clientdata);
        }
        equiv = equiv->next;
      }
    }

Patch to be tested

  for (i = 0; i < swig_module.size; i++) {
    if (swig_module.types[i]->clientdata) {
      equiv = swig_module.types[i]->cast;
      while (equiv) {
        if (!equiv->converter) {
          if (equiv->type && !equiv->type->clientdata)                                                                                                                                                     
            SWIG_TypeClientData(equiv->type, swig_module.types[i]->clientdata);
        }
        if (equiv == equiv->next) {
            break;
        }
        equiv = equiv->next;
      }
    }