### Description
Investigating a report on a Kamailio crash, it led to pdb module, with the following backtrace:
``` #0 0x0000000000000000 in ?? () #1 0x00007f870472fa33 in vfprintf () from /lib64/libc.so.6 #2 0x00007f87047562bb in vsprintf () from /lib64/libc.so.6 #3 0x00007f8704738457 in sprintf () from /lib64/libc.so.6 #4 0x00007f86f881c6f9 in pdb_msg_dbg (msg=..., dbg_msg=0x7f86f8828313 "Kamailio pdb client receives:") at pdb.c:152 #5 0x00007f86f88204e4 in pdb_query (_msg=0x7f8700fae068, _number=0x7f8700fa2e88, _dstavp=0x7f8700fa2f10) at pdb.c:335 #6 0x000000000047b72c in do_action (h=0x7ffeb03d10e0, a=0x7f8700abf678, msg=0x7f8700fae068) at core/action.c:1079 #7 0x0000000000487e70 in run_actions (h=0x7ffeb03d10e0, a=0x7f8700abf678, msg=0x7f8700fae068) at core/action.c:1569 #8 0x0000000000488531 in run_actions_safe (h=0x7ffeb03d3180, a=0x7f8700abf678, msg=0x7f8700fae068) at core/action.c:1633 #9 0x0000000000447f40 in rval_get_int (h=0x7ffeb03d3180, msg=0x7f8700fae068, i=0x7ffeb03d18b0, rv=0x7f8700ac0148, cache=0x0) at core/rvalue.c:912 #10 0x000000000044c4f0 in rval_expr_eval_int (h=0x7ffeb03d3180, msg=0x7f8700fae068, res=0x7ffeb03d18b0, rve=0x7f8700ac0140) at core/rvalue.c:1910 ```
Looking at the data in frame 4, it looks that an empty (0-ed) pdb structure is printed:
``` (gdb) frame 4 #4 0x00007f86f881c6f9 in pdb_msg_dbg (msg=..., dbg_msg=0x7f86f8828313 "Kamailio pdb client receives:") at pdb.c:152 152 ptr += sprintf(ptr,"%02X ", msg.bdy.payload[i]); (gdb) p i $1 = 263 (gdb) p msg $2 = {hdr = {version = 0 '\000', type = 0 '\000', code = 0 '\000', length = 0 '\000', id = 0}, bdy = {payload = '\000' <repeats 248 times>}} (gdb) p msg.hdr.length $3 = 0 '\000' ``` I just pushed commit 3c07e2351a94e4ff2cf3c6b9b9df4d7462cd5760 for a safety check, but not being the developer of the module, I am not sure it is supposed to deal with a 0-ed pdb structure, or the issue is somewhere else, leading to this 0-only structure content.
Therefore I am opening this one for further analyze, if the commit above is enough, just close the issue.
### Troubleshooting
#### Reproduction
Try to send traffic to a config using pdb matching PDB_VERSION_1.
#### Debugging Data
``` gdb backtrace above ```
#### Log Messages
``` N/A ```
#### SIP Traffic
``` N/A ```
### Possible Solutions
### Additional Information
* **Kamailio Version** - output of `kamailio -v`
``` kamailio -v version: kamailio 5.2.3 (x86_64/linux) c36229 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: c36229 compiled on 10:34:54 Jun 13 2019 with gcc 4.8.5 ```
* **Operating System**:
``` CentOS 7 with Kamailio installed from RPM (using opensuse build service repo) ```