I have been receiving CRITICAL core logs since I have updated my service to the following version.
Print out of kamailio internals
Version: kamailio 5.1.5 (x86_64/linux) d06080
Default config: /usr/local/SIPSer/etc/kamailio/kamailio.cfg
Default paths to modules: /usr/local/SIPSer/lib64/kamailio/modules
Compile 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
MAX_RECV_BUFFER_SIZE=262144
MAX_URI_SIZE=1024
BUF_SIZE=65535
DEFAULT PKG_SIZE=8MB
DEFAULT SHM_SIZE=64MB
ADAPTIVE_WAIT_LOOPS=1024
TCP poll methods: poll, epoll_lt, epoll_et, sigio_rt, select
Source code revision ID: d06080
Compiled with: gcc 4.8.5
Compiled on: 14:17:56 Sep 13 2018
Thank you for flying kamailio!
$ /usr/local/sbin/kamailio -P /run/kamailio/kamailio.pid -f /usr/local/etc/kamailio/kamailio.cfg -m 1024 -M 512
Sep 27 14:40:19 kamailio_eu SIPSer[11289]: 923226363266 923000000001 27872 INVITE haYKxpYM1QR8XTU37WdVbxf4VkEITe7A CRITICAL: <core> [core/mem/q_malloc.c:504]: qm_free(): BUG: freeing already freed pointer (0x7f30c8a4df30), called
from tm: t_reply.c: relay_reply(1920), first free tm: h_table.c: free_cell_helper(155) - aborting
Sep 27 14:40:19 kamailio_eu SIPSer[11289]: 923226363266 923000000001 27872 INVITE haYKxpYM1QR8XTU37WdVbxf4VkEITe7A CRITICAL: <core> [core/mem/q_malloc.c:504]: qm_free(): BUG: freeing already freed pointer (0x7f30c8a4cc40),
called from tm: h_table.c: free_cell_helper(153), first free tm: h_table.c: free_cell_helper(153) - aborting