(gdb) bt
#0  0xb77a6f34 in _ao2_unlock@plt () from /usr/lib/asterisk/modules/res_timing_pthread.so
#1  0xb77a7d66 in pthread_timer_ack (handle=1090, quantity=1) at res_timing_pthread.c:200
#2  0x080b4f4d in __ast_read (chan=0x8b69b10, dropaudio=0) at channel.c:2643
#3  0x081130df in waitstream_core (c=0x8b69b10, breakon=0xb78dc2cb "", forward=0x81fbf1f "", 
    reverse=0x81fbf1f "", skip_ms=0, audiofd=-1, cmdfd=-1, context=0x0) at file.c:1232
#4  0x081135d8 in ast_waitstream (c=0x8b69b10, breakon=0xb78dc2cb "") at file.c:1317
#5  0xb78db554 in playback_exec (chan=0x8b69b10, data=0xb2b40fa8) at app_playback.c:445
#6  0x081634e0 in pbx_exec (c=0x8b69b10, app=0x8330e88, data=0xb2b40fa8) at pbx.c:960
#7  0x08179e5a in pbx_extension_helper (c=0x8b69b10, con=0x0, context=0x8b6a390 "test11", 
    exten=0x8b6a3e0 "12", priority=2, label=0x0, callerid=0x8acddc8 "sipp", action=E_SPAWN, 
    found=0xb2b433e8, combined_find_spawn=1) at pbx.c:3219
#8  0x0817cadf in __ast_pbx_run (c=0x8b69b10, args=0x0) at pbx.c:3675
#9  0x0817ea60 in pbx_thread (data=0x8b69b10) at pbx.c:4051
#10 0x081d5feb in dummy_start (data=0x8b000f0) at utils.c:968
#11 0xb7c8e240 in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#12 0xb7d6a49e in clone () from /lib/tls/i686/cmov/libc.so.6