(gdb) taa bt

Thread 13 (LWP 1 of process 1916):
#0  0x000072c8ac51b65a in recvmsg () from /usr/lib/libc.so.12
#1  0x000072c89d817d89 in _xcb_in_read () from /usr/X11R7/lib/libxcb.so.2
#2  0x000072c89d81873f in xcb_poll_for_event () from /usr/X11R7/lib/libxcb.so.2
#3  0x000072c8a24485c8 in ?? () from /usr/X11R7/lib/libX11.so.7
#4  0x000072c8a2448728 in ?? () from /usr/X11R7/lib/libX11.so.7
#5  0x000072c8a24489bb in _XEventsQueued () from /usr/X11R7/lib/libX11.so.7
#6  0x000072c8a242beac in XPending () from /usr/X11R7/lib/libX11.so.7
#7  0x000072c8b1a66a4b in gdk_event_source_prepare () from /usr/pkg/lib/libgdk-3.so.0
#8  0x000072c8b5848cc8 in g_main_context_prepare () from /usr/pkg/lib/libglib-2.0.so.0
#9  0x000072c8b5849580 in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#10 0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#11 0x000072c8b2015202 in gtk_main () from /usr/pkg/lib/libgtk-3.so.0
#12 0x000000000041646e in main (argc=1, argv=0x7f7fff652168) at luakit.c:254

Thread 12 (LWP 2 of process 1916):
#0  0x000072c8ac4a1f7a in ___lwp_park60 () from /usr/lib/libc.so.12
#1  0x000072c8aca0a71f in pthread_cond_timedwait () from /usr/lib/libpthread.so.1
#2  0x000072c8a00a1412 in std::condition_variable::wait(std::unique_lock<std::mutex>&) () from /usr/lib/libstdc++.so.9
#3  0x000072c8ae28da2e in bmalloc::Scavenger::threadRunLoop() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#4  0x000072c8ae28e0e1 in bmalloc::Scavenger::threadEntryPoint(bmalloc::Scavenger*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8a009f5aa in ?? () from /usr/lib/libstdc++.so.9
#6  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#7  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#8  0x00010102464c457f in ?? ()
#9  0x0000000000000000 in ?? ()

Thread 11 (LWP 3 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x000072c8b5bf37b0 in ?? ()
#10 0x000072c8b5bf37b0 in ?? ()
#11 0x0000000000000001 in ?? ()
#12 0x000072c852402678 in ?? ()
#13 0x000072c8524010d0 in ?? ()
#14 0x0000000000000000 in ?? ()

Thread 10 (LWP 4 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 9 (LWP 5 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 8 (LWP 6 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b5849740 in g_main_context_iteration () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8b5849776 in glib_worker_main () from /usr/pkg/lib/libglib-2.0.so.0
#5  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#6  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#7  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#8  0x0000000000000000 in ?? ()

Thread 7 (LWP 7 of process 1916):
#0  0x000072c8ac442c5a in accept () from /usr/lib/libc.so.12
#1  0x000072c8aca077e7 in accept () from /usr/lib/libpthread.so.1
#2  0x00000000004149f0 in web_extension_connect_thread (UNUSED_data=0x0) at ipc.c:161
#3  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#5  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#6  0x00010102464c457f in ?? ()
#7  0x0000000000000000 in ?? ()

Thread 6 (LWP 8 of process 1916):
#0  0x000072c8ac4a1f7a in ___lwp_park60 () from /usr/lib/libc.so.12
#1  0x000072c8aca0a71f in pthread_cond_timedwait () from /usr/lib/libpthread.so.1
#2  0x000072c8b588d690 in g_cond_wait () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b581e6c8 in g_async_queue_pop_intern_unlocked () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8b586e61e in g_thread_pool_spawn_thread () from /usr/pkg/lib/libglib-2.0.so.0
#5  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#6  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#7  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#8  0x00010102464c457f in ?? ()
#9  0x0000000000000000 in ?? ()

Thread 5 (LWP 9 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8af6fc068 in gdbus_shared_thread_func () from /usr/pkg/lib/libgio-2.0.so.0
#5  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#6  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#7  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#8  0x0000000000000000 in ?? ()

Thread 4 (LWP 11 of process 1916):
#0  0x000072c8ac4a1f7a in ___lwp_park60 () from /usr/lib/libc.so.12
#1  0x000072c8aca0a71f in pthread_cond_timedwait () from /usr/lib/libpthread.so.1
#2  0x000072c8b588d690 in g_cond_wait () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b581e6c8 in g_async_queue_pop_intern_unlocked () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8b581ea32 in g_async_queue_pop () from /usr/pkg/lib/libglib-2.0.so.0
#5  0x000000000041b709 in ipc_send_thread (UNUSED_user_data=0x0) at common/ipc.c:75
#6  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 3 (LWP 12 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 2 (LWP 13 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1


Thread 4 (LWP 11 of process 1916):
#0  0x000072c8ac4a1f7a in ___lwp_park60 () from /usr/lib/libc.so.12
#1  0x000072c8aca0a71f in pthread_cond_timedwait () from /usr/lib/libpthread.so.1
#2  0x000072c8b588d690 in g_cond_wait () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b581e6c8 in g_async_queue_pop_intern_unlocked () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8b581ea32 in g_async_queue_pop () from /usr/pkg/lib/libglib-2.0.so.0
#5  0x000000000041b709 in ipc_send_thread (UNUSED_user_data=0x0) at common/ipc.c:75
#6  0x000072c8b586e0c5 in g_thread_proxy () from /usr/pkg/lib/libglib-2.0.so.0
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 3 (LWP 12 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 2 (LWP 13 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
--Type <RET> for more, q to quit, c to continue without paging--
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()

Thread 1 (LWP 15 of process 1916):
#0  0x000072c8ac4429ba in poll () from /usr/lib/libc.so.12
#1  0x000072c8aca07d52 in poll () from /usr/lib/libpthread.so.1
#2  0x000072c8b584960a in g_main_context_iterate.isra () from /usr/pkg/lib/libglib-2.0.so.0
#3  0x000072c8b584991a in g_main_loop_run () from /usr/pkg/lib/libglib-2.0.so.0
#4  0x000072c8ae27fd3f in WTF::RunLoop::run() () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#5  0x000072c8ae257e1b in WTF::Thread::entryPoint(WTF::Thread::NewThreadContext*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#6  0x000072c8ae280bd0 in WTF::wtfThreadEntryPoint(void*) () from /usr/pkg/lib/libjavascriptcoregtk-4.0.so.18
#7  0x000072c8aca0c072 in ?? () from /usr/lib/libpthread.so.1
#8  0x000072c8ac487af0 in ?? () from /usr/lib/libc.so.12
#9  0x0000000000000000 in ?? ()
(gdb) 


dtruss summary while frozen:
CALL                                        COUNT
_lwp_park                                       3
clock_gettime                                 333
poll                                          333
recvmsg                                       333
write                                         665
read                                          666