[OpenSIPS-Devel] Finding a memory leak

[John Quick]

Please can someone provide advice on interpreting OpenSIPS memory dumps and
identifying the cause of a memory leak.

A Proxy application I wrote, running v2.1.4 with DBG_QM_MALLOC enabled, is
leaking package memory so badly that I have to restart the service once a
week.

When I use this command:
        opensipsctl fifo get_statistics pkmem: | grep max
...it lists 57 lines of output. Most of these show a similar value from day
to day, but there are three instances near the middle of the list that
increase from one day to the next. For example:
pkmem:0-max_used_size:: 1359072
pkmem:1-max_used_size:: 1427568
pkmem:2-max_used_size:: 1463256
...
pkmem:23-max_used_size:: 3013848
pkmem:24-max_used_size:: 2541240
pkmem:25-max_used_size:: 3799672
...
pkmem:55-max_used_size:: 1420112
pkmem:56-max_used_size:: 1422104
pkmem:57-max_used_size:: 1396384

When I trigger a memory report (dump) using the command 
        kill -SIGUSR1 971
...the resulting output in my opensips.log file looks almost the same from
one day top the next.

Do I need to use a different Process ID so I can get a memory dump for the
pkmem:25 child thread?
If so, how do I know which PID to use?  The command "ps ax | grep opensips"
returns a list of 59 process ID's.
Even if I get the right PID, what am I looking for in the memory dump?
Typical memory dump output looks like this:
2016-12-15 15:54:44       41. N  address=0x7f4be8db9048 frag=0x7f4be8db9018
size=48 used=1
2016-12-15 15:54:44              alloc'd from sr_module.c:
register_module(151)
2016-12-15 15:54:44          start check=f0f0f0f0f0f0f0f0, end check=
c0c0c0c0c0c0c0c0, abcdefedabcdefed
2016-12-15 15:54:44       42. N  address=0x7f4be8db90d8 frag=0x7f4be8db90a8
size=128 used=1
2016-12-15 15:54:44              alloc'd from cfg.lex: addstr(925)
2016-12-15 15:54:44          start check=f0f0f0f0f0f0f0f0, end check=
c0c0c0c0c0c0c0c0, abcdefedabcdefed
...
2016-12-15 15:54:44       63. N  address=0x7f4be8db9f70 frag=0x7f4be8db9f40
size=80 used=1
2016-12-15 15:54:44              alloc'd from pvar.c: pv_add_extra(4480)
2016-12-15 15:54:44          start check=f0f0f0f0f0f0f0f0, end check=
c0c0c0c0c0c0c0c0, abcdefedabcdefed
2016-12-15 15:54:44       64. N  address=0x7f4be8dba020 frag=0x7f4be8db9ff0
size=80 used=1
2016-12-15 15:54:44              alloc'd from pvar.c: pv_add_extra(4480)

I have not found any cases where the value for "frag size" exceeds 240. The
line that starts "alloc'd from" never seems to have a value in parentheses
exceeding 4480.
I cannot see anything that looks like a smoking gun.  The list never goes
beyond item 64.

John Quick
Smartvox Limited
Tel:   +44-1727-221221