jsonrpcs_exec for the rtpengine cache gives memory leak

[ovoshlook]

Description

We are buidling some kind of our own rtpengine dispatcher based on our own algorithm using kemi Lua.

In one of the functions we are calling:

local reqBody = function(command, params)

    return json.encode({
        jsonrpc = "2.0",
        method = "rtpengine." .. command,
        params = params
    })

end

KSR.jsonrpcs.exec(reqBody("show", { "all" }))
local data = json.decode(KSR.pv.get("$jsonrpl(body)"))

And watching free_mem decrasing in case of every call of this function

If we are commenting this - nothing happens

P.S. We are doing the same for the dispatcher module but did not find memory leak for it:

local reqBody = function (command,params)

    return  json.encode( { 
        jsonrpc = "2.0", 
        method  = "dispatcher." ..command, 
        params  = params 
    } )

end

KSR.jsonrpcs.exec(reqBody( "list" ) )
local data = json.decode( KSR.pv.get("$jsonrpl(body)") )

Troubleshooting

Reproduction

To reproduce this issue suppose will be enough to call code above

Debugging Data

test results for 10000 calls total/300 per second (sipp based)

memory stats on the start

shmem:free_size = 63131408 
shmem:max_used_size = 3994704 
shmem:real_used_size = 3977456 
shmem:total_size = 67108864
shmem:used_size = 3205144

memory stats on the end ( free_size never incrases after calls. Only decrases after new call)

shmem:fragments = 5 |  
shmem:free_size = 60106232 
shmem:max_used_size = 7019952 
shmem:real_used_size = 7002632
shmem:total_size = 67108864
shmem:used_size = 4150008

Additional Information

• Kamailio Version - output of kamailio -v

version: kamailio 5.1.6 (x86_64/linux) 7d1964
flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES
ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144 MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: 7d1964
compiled on 03:23:23 Oct  5 2018 with gcc 6.3.0

• Operating System:

1 machine: SMP Debian 4.9.110-3+deb9u6 (2018-10-08) x86_64 GNU/Linux
2 machine: SMP Debian 4.9.110-3+deb9u2 (2018-08-13) x86_64 GNU/Linux

If will need any additional info just let me know
P.S. We also tried to find what can give this behavior on the rtpengine.c but didn't figured out yet

[ovoshlook]

found reason
It was about
rtpeninge.rtp.manage()
we did not expect behavior that if not call manage for the BYE request - it will keep something in the memory of the kamailio