(gdb) thread apply all bt

Thread 12 (process 10218):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x16ebb40, nfds=1, timeout=4) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeae5c2c9 in g_main_context_iterate (context=0x1136070, block=1, dispatch=1,
    self=<value optimized out>) at gmain.c:2768
#2  0x00007ffaeae5c8bd in IA__g_main_loop_run (loop=0x16e9e70) at gmain.c:2663
#3  0x00007ffaee5cc577 in IA__gtk_main () at gtkmain.c:1205
#4  0x000000000046444c in inner_main (closure=<value optimized out>, argc=<value optimized out>,
    argv=<value optimized out>) at view.c:3361
#5  0x00007ffaf0511cff in invoke_main_func (body_data=0x7fff6b2a2cb0) at init.c:367
#6  0x00007ffaf04e8ada in c_body (d=0x7fff6b2a2c50) at continuations.c:350
#7  0x00007ffaf054f03f in scm_c_catch (tag=0x104, body=0x7ffaf04e8ad0 <c_body>, body_data=0x7fff6b2a2c50,
    handler=0x7ffaf04e8af0 <c_handler>, handler_data=0x7fff6b2a2c50,
    pre_unwind_handler=0x7ffaf054e6f0 <scm_handle_by_message_noexit>, pre_unwind_handler_data=0x0) at throw.c:200
#8  0x00007ffaf04e8f91 in scm_i_with_continuation_barrier (body=0x7ffaf04e8ad0 <c_body>,
    body_data=0x7fff6b2a2c50, handler=0x7ffaf04e8af0 <c_handler>, handler_data=0x7fff6b2a2c50,
    pre_unwind_handler=0x7ffaf054e6f0 <scm_handle_by_message_noexit>, pre_unwind_handler_data=0x0)
    at continuations.c:326
#9  0x00007ffaf04e9030 in scm_c_with_continuation_barrier (func=<value optimized out>, data=<value optimized out>)
    at continuations.c:368
#10 0x00007ffaf054dfc3 in scm_i_with_guile_and_parent (func=0x7ffaf0511ce0 <invoke_main_func>,
    data=0x7fff6b2a2cb0, parent=<value optimized out>) at threads.c:695
#11 0x00007ffaf0511cc5 in scm_boot_guile (argc=<value optimized out>, argv=<value optimized out>, main_func=0x4,
    closure=0xffffffffffffffff) at init.c:350
#12 0x000000000043b16c in main (argc=1, argv=0x7fff6b2a2dc8) at main.c:496

Thread 11 (process 10221):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14c0670, nfds=1, timeout=1000)
    at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a59b in jack_client_event_loop (client=0x14e0ea0) at client.c:1586
#2  0x00007ffaeac0b1f1 in jack_client_thread (arg=0x14e0ea0) at client.c:2073
#3  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#4  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 10 (process 10227):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e47e0, nfds=1, timeout=1000)
    at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a59b in jack_client_event_loop (client=0x14e80a0) at client.c:1586
#2  0x00007ffaeac0b1f1 in jack_client_thread (arg=0x14e80a0) at client.c:2073
#3  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#4  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 9 (process 10230):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e3a40, nfds=1, timeout=1000)
    at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a59b in jack_client_event_loop (client=0x14e9530) at client.c:1586
#2  0x00007ffaeac0b1f1 in jack_client_thread (arg=0x14e9530) at client.c:2073
#3  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#4  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 8 (process 10233):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e4d50, nfds=1, timeout=1000)
    at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a59b in jack_client_event_loop (client=0x14ea9c0) at client.c:1586
#2  0x00007ffaeac0b1f1 in jack_client_thread (arg=0x14ea9c0) at client.c:2073
#3  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#4  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 7 (process 10219):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:261
#1  0x00007ffaeac0ce6d in mb_thread_func (arg=0x0) at messagebuffer.c:72
#2  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#3  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#4  0x0000000000000000 in ?? ()

Thread 6 (process 10224):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e62f0, nfds=1, timeout=1000)
    at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a59b in jack_client_event_loop (client=0x14e2330) at client.c:1586
#2  0x00007ffaeac0b1f1 in jack_client_thread (arg=0x14e2330) at client.c:2073
#3  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#4  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()
Current language:  auto; currently asm

Thread 5 (process 10231):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e3a48, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a646 in jack_client_graph_wait (client=0x14e9530) at client.c:1639
#2  0x00007ffaeac0ae39 in jack_thread_wait (client=0x14e9530, status=0) at client.c:1932
#3  0x00007ffaeac0b0bf in jack_process_thread_aux (arg=0x14e9530) at client.c:2032
#4  0x00007ffaeac0b262 in jack_client_process_thread (arg=0x14e9530) at client.c:2088
#5  0x00007ffaeac105a6 in jack_thread_proxy (varg=0x14ca120) at thread.c:118
#6  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#7  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#8  0x0000000000000000 in ?? ()
Current language:  auto; currently c

Thread 4 (process 10228):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e47e8, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a646 in jack_client_graph_wait (client=0x14e80a0) at client.c:1639
#2  0x00007ffaeac0ae39 in jack_thread_wait (client=0x14e80a0, status=0) at client.c:1932
#3  0x00007ffaeac0b0bf in jack_process_thread_aux (arg=0x14e80a0) at client.c:2032
#4  0x00007ffaeac0b262 in jack_client_process_thread (arg=0x14e80a0) at client.c:2088
#5  0x00007ffaeac105a6 in jack_thread_proxy (varg=0x14e3a40) at thread.c:118
#6  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#7  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#8  0x0000000000000000 in ?? ()

Thread 3 (process 10225):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14e62f8, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a646 in jack_client_graph_wait (client=0x14e2330) at client.c:1639
#2  0x00007ffaeac0ae39 in jack_thread_wait (client=0x14e2330, status=0) at client.c:1932
#3  0x00007ffaeac0b0bf in jack_process_thread_aux (arg=0x14e2330) at client.c:2032
#4  0x00007ffaeac0b262 in jack_client_process_thread (arg=0x14e2330) at client.c:2088
#5  0x00007ffaeac105a6 in jack_thread_proxy (varg=0x14e47e0) at thread.c:118
#6  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#7  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#8  0x0000000000000000 in ?? ()

Thread 2 (process 10222):
#0  0x00007ffae9d5baf6 in *__GI___poll (fds=0x14c0678, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffaeac0a646 in jack_client_graph_wait (client=0x14e0ea0) at client.c:1639
#2  0x00007ffaeac0ae39 in jack_thread_wait (client=0x14e0ea0, status=0) at client.c:1932
#3  0x00007ffaeac0b0bf in jack_process_thread_aux (arg=0x14e0ea0) at client.c:2032
#4  0x00007ffaeac0b262 in jack_client_process_thread (arg=0x14e0ea0) at client.c:2088
#5  0x00007ffaeac105a6 in jack_thread_proxy (varg=0x14e4d50) at thread.c:118
#6  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#7  0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#8  0x0000000000000000 in ?? ()

Thread 1 (process 10234):
#0  0x00007ffae9cc6205 in *__GI_raise (sig=<value optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#1  0x00007ffae9cc7723 in *__GI_abort () at abort.c:88
#2  0x00007ffae9cbf229 in *__GI___assert_fail (
    assertion=0x7ffaeac12d90 "out_info->event_count == num_events - out_info->events_lost",
    file=0x7ffaeac12d80 "midiport.c", line=312, function=0x7ffaeac12dd0 "jack_midi_port_mixdown") at assert.c:78
#3  0x00007ffaeac0ee4f in jack_midi_port_mixdown (port=0x14e4db0, nframes=256) at midiport.c:312
#4  0x00007ffaeac0e023 in jack_port_get_buffer (port=0x14e4db0, nframes=256) at port.c:569
#5  0x0000000000478ff0 in process_callback (nframes=256, client_number=4) at jackmidi.c:287
#6  0x00007ffaeac0b078 in jack_process_thread_aux (arg=0x14ea9c0) at client.c:2029
#7  0x00007ffaeac0b262 in jack_client_process_thread (arg=0x14ea9c0) at client.c:2088
#8  0x00007ffaeac105a6 in jack_thread_proxy (varg=0x14e6b10) at thread.c:118
#9  0x00007ffaea7e8007 in start_thread (arg=<value optimized out>) at pthread_create.c:297
#10 0x00007ffae9d6448d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()