Deadlock between ioqueue key mutex and SIP dialog when adding video media with ICE and STUN enabled

[bennylp]

This happens because create_ice_media_transport() calls handle_events() while holding dialog mutex, thus will cause deadlock if a worker thread is receiving a message and wants to acquire the dialog mutex.

Sample scenario:

• Thread 1: add video, create ice transport, holding dialog mutex, polling for events, got data, acquiring ioqueue key mutex
• Thread 8: incoming request, holding ioqueue key mutex, acquiring dialog, fail and retry forever

Thread [1] (Suspended: Signal 'SIGINT' received. Description: Interrupt.)	
	18 __lll_lock_wait()  
	17 _L_lock_903()  
	16 pthread_mutex_lock()  
	15 pj_mutex_lock() ~/pjlib/src/pj/os_core_unix.c:1243
	14 pj_lock_acquire() ~/pjlib/src/pj/lock.c:180
	13 pj_ioqueue_lock_key() ~/pjlib/src/pj/ioqueue_common_abs.c:1324
	12 ioqueue_dispatch_read_event() ~/pjlib/src/pj/ioqueue_common_abs.c:428 
	11 pj_ioqueue_poll() ~/pjlib/src/pj/ioqueue_select.c:963 
	10 pjsip_endpt_handle_events2() ~/pjsip/src/pjsip/sip_endpoint.c:741 
	9 pjsua_handle_events() ~/pjsip/src/pjsua-lib/pjsua_core.c:1833 
	8 create_ice_media_transport() ~/pjsip/src/pjsua-lib/pjsua_media.c:836 
	7 pjsua_call_media_init() ~/pjsip/src/pjsua-lib/pjsua_media.c:1336 
	6 call_add_video() ~/pjsip/src/pjsua-lib/pjsua_vid.c:1555 
	5 pjsua_call_set_vid_strm() ~/pjsip/src/pjsua-lib/pjsua_vid.c:2087 
	4 vid_handle_menu()  
	3 legacy_main()  
	2 pjsua_app_run()  
	1 main()  


Thread [8] (Suspended)	
	18 nanosleep()  
	17 usleep()  
	16 pj_thread_sleep() ~/pjlib/src/pj/os_core_unix.c:760 
	15 mod_ua_on_rx_request() ~/pjsip/src/pjsip/sip_ua_layer.c:685 
	14 pjsip_endpt_process_rx_data() ~/pjsip/src/pjsip/sip_endpoint.c:886 
	13 endpt_on_rx_msg() ~/pjsip/src/pjsip/sip_endpoint.c:1036 
	12 pjsip_tpmgr_receive_packet() ~/pjsip/src/pjsip/sip_transport.c:1764 
	11 on_data_read() ~/pjsip/src/pjsip/sip_transport_tcp.c:1300 
	10 ioqueue_on_read_complete() ~/pjlib/src/pj/activesock.c:490 
	9 ioqueue_dispatch_read_event() ~/pjlib/src/pj/ioqueue_common_abs.c:591 
	8 pj_ioqueue_poll() ~/pjlib/src/pj/ioqueue_select.c:963 
	7 pjsip_endpt_handle_events2() ~/pjsip/src/pjsip/sip_endpoint.c:741 
	6 pjsua_handle_events() ~/pjsip/src/pjsua-lib/pjsua_core.c:1833 
	5 worker_thread() ~/pjsip/src/pjsua-lib/pjsua_core.c:694 
	4 thread_main() ~/pjlib/src/pj/os_core_unix.c:523 
	3 start_thread()  
	2 clone()  
	1 <symbol is not available> 

[bennylp]

In 4749:

Fixed #1737: Deadlock between ioqueue key mutex and SIP dialog when adding video media with ICE and STUN enabled