===
=== <pending> <lock#> (<file>): <lock type> <line num> <function> <lock name> <lock addr> (times locked)
===
=== Thread ID: 0x7f9eeaadc700 (pbx_thread           started at [ 6612] pbx.c ast_pbx_start())
=== ---> Lock #0 (channel.c): MUTEX 4943 ast_write chan 0x7f9f04f32e00 (1)
        /usr/sbin/asterisk(ast_bt_get_addresses+0x1d) [0x5107aa]
        /usr/sbin/asterisk(__ast_pthread_mutex_trylock+0xe0) [0x508884]
        /usr/sbin/asterisk(__ao2_trylock+0x93) [0x44dc14]
        /usr/sbin/asterisk(ast_write+0x117) [0x48134f]
        /usr/sbin/asterisk() [0x48b024]
        /usr/sbin/asterisk(ast_channel_bridge+0x1939) [0x48d459]
        /usr/sbin/asterisk(ast_bridge_call+0xfcf) [0x4d987d]
        /usr/lib/asterisk/modules/app_dial.so(+0x1053c) [0x7f9f0095253c]
        /usr/lib/asterisk/modules/app_dial.so(+0x10bbe) [0x7f9f00952bbe]
        /usr/sbin/asterisk(pbx_exec+0x214) [0x532ca5]
        /usr/lib/asterisk/modules/res_agi.so(+0xbba7) [0x7f9f0b9b9ba7]
        /usr/lib/asterisk/modules/res_agi.so(+0xe78d) [0x7f9f0b9bc78d]
        /usr/lib/asterisk/modules/res_agi.so(+0xf2f0) [0x7f9f0b9bd2f0]
        /usr/lib/asterisk/modules/res_agi.so(+0x10881) [0x7f9f0b9be881]
        /usr/lib/asterisk/modules/res_agi.so(+0x109bc) [0x7f9f0b9be9bc]
        /usr/sbin/asterisk(pbx_exec+0x214) [0x532ca5]
        /usr/sbin/asterisk() [0x53d351]
        /usr/sbin/asterisk(ast_spawn_extension+0x64) [0x540920]
        /usr/sbin/asterisk() [0x542095]
        /usr/sbin/asterisk() [0x543b84]
        /usr/sbin/asterisk() [0x5a38c1]
        /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a) [0x7f9f42bc1e9a]
        /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d) [0x7f9f43d073fd]