**Description**

Recently we have upgraded to **kamailio 5.3** version and we are performing load tests on it for scalability but Unfortunately it is **crashed** while performing in **ims_dialog** module. we are using **ims_dialog** module instead of **dialog** module for **diameter** protocol purpose.

**Troubleshooting**

We found out that **dlg_out** is **NULL** but we are accessing the **dlg_out->to_tag.len** this leads to the crash..But unfortunately we don't know how this gets **NULL** as **dlg_out** is assigned to **d_entry_out->first** which is **NOT NULL**

**GDB messages:**

(gdb) #0 0x00007fbe5a646ea6 in next_state_dlg (dlg=0x7fbe57dcf268, event=3, old_state=0x7ffc8b03f0a0, new_state=0x7ffc8b03f0a4, unref=0x7ffc8b03f09c, to_tag=0x7ffc8b03f080) at dlg_hash.c:1180 #1 0x00007fbe5a622170 in dlg_onreply (t=0x7fbe57f7a3f0, type=1048576, param=0x7ffc8b03f2f0) at dlg_handlers.c:1276 #2 0x00007fbe5e2b5517 in run_trans_callbacks_internal (cb_lst=0x7fbe57f7a468, type=1048576, trans=0x7fbe57f7a3f0, params=0x7ffc8b03f2f0) at t_hooks.c:254 #3 0x00007fbe5e2b5733 in run_trans_callbacks_with_buf (type=1048576, rbuf=0x7fbe57f7a4c0, req=0x7fbe57f7bab0, repl=0x7fbe5fa1d218, flags=0) at t_hooks.c:297 #4 0x00007fbe5e2fc05f in relay_reply (t=0x7fbe57f7a3f0, p_msg=0x7fbe5fa1d218, branch=1, msg_status=183, cancel_data=0x7ffc8b03f760, do_put_on_wait=1) at t_reply.c:1986 #5 0x00007fbe5e300ec3 in reply_received (p_msg=0x7fbe5fa1d218) at t_reply.c:2540 #6 0x00000000004b6f43 in do_forward_reply (msg=0x7fbe5fa1d218, mode=0) at core/forward.c:745 #7 0x00000000004b8a8f in forward_reply (msg=0x7fbe5fa1d218) at core/forward.c:846 #8 0x00000000005527c7 in receive_msg ( buf=0xb3b740 "SIP/2.0 183 Session Progress\r\nVia: SIP/2.0/UDP 182.72.244.91:5060;branch=z9hG4bK7fea.85af5c92096548bdd857481789b3e50f.1, SIP/2.0/UDP 182.72.244.91:5080;received=182.72.244.91;rport=5080;branch=z9hG4bK"..., len=613, rcv_info=0x7ffc8b040000) at core/receive.c:510 #9 0x0000000000675077 in udp_rcv_loop () at core/udp_server.c:548 #10 0x0000000000425f4b in main_loop () at main.c:1673 #11 0x000000000042e52a in main (argc=13, argv=0x7ffc8b040808) at main.c:2802

*******************************************************************************

(gdb) f 0 #0 0x00007fbe5a646ea6 in next_state_dlg (dlg=0x7fbe57dcf268, event=3, old_state=0x7ffc8b03f0a0, new_state=0x7ffc8b03f0a4, unref=0x7ffc8b03f09c, to_tag=0x7ffc8b03f080) at dlg_hash.c:1180 1180 if (dlg_out->to_tag.len == to_tag->len && memcmp(dlg_out->to_tag.s, to_tag->s, dlg_out->to_tag.len) == 0) { (gdb) info locals d_entry = 0x7fbe57d5ab70 d_entry_out = 0x7fbe57dcf378 dlg_out = 0x0 found = -1 delete = 1 __FUNCTION__ = "next_state_dlg" (gdb) p d_entry_out->first $10 = (struct dlg_cell_out *) 0x7fbe57fcf6b8

**Additional Information**

**version**: kamailio 5.3.2 (x86_64/linux)

Thanks in Advance...I am beginning to work with kamailio ....can you guys please give me some hints how to move forward with this..