AddressSanitizer:DEADLYSIGNAL
=================================================================
==2416407==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000a38 (pc 0x7fabc7173255 bp 0x7fabbecfca80 sp 0x7fabbecfca68 T1)
==2416407==The signal is caused by a WRITE memory access.
==2416407==Hint: address points to the zero page.
Frame::on_size_allocate 266x43 < 213x144
Frame::on_size_allocate 266x48 < 204x148
Frame::on_size_allocate 266x10 < 266x110
    #0 0x7fabc7173255 in g_mutex_lock (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0xa4255)
    0000001 0x56064123a139 in Glib::Threads::Mutex::Lock::Lock(Glib::Threads::Mutex&) /usr/include/glibmm-2.4/glibmm/threads.h:687
    #2 0x560641289306 in PBD::SignalWithCombiner<PBD::OptionalLastValue<void>, void ()>::_connect(PBD::EventLoop::InvalidationRecord*, std::function<void ()>) ../libs/pbd/pbd/signals.h:600
    #3 0x5606414ff723 in PBD::SignalWithCombiner<PBD::OptionalLastValue<void>, void ()>::connect_same_thread(PBD::ScopedConnection&, std::function<void ()> const&) ../libs/pbd/pbd/signals.h:347
    0000004 0x7fabcbfe4b6e in ARDOUR::MIDITrigger::set_region_in_worker_thread(std::shared_ptr<ARDOUR::Region>) ../libs/ardour/triggerbox.cc:3088
    0000005 0x7fabcbff82c8 in ARDOUR::TriggerBox::set_region(unsigned int, std::shared_ptr<ARDOUR::Region>) ../libs/ardour/triggerbox.cc:4240
    #6 0x7fabcc00dd9a in ARDOUR::TriggerBoxThread::thread_work() ../libs/ardour/triggerbox.cc:5731
    #7 0x7fabcc00d9bd in ARDOUR::TriggerBoxThread::_thread_work(void*) ../libs/ardour/triggerbox.cc:5707
    0000008 0x7fabc7cd7cd5 in fake_thread_start ../libs/pbd/pthread_utils.cc:199
    0000009 0x7fabc80b8ea6 in start_thread nptl/pthread_create.c:477
    0000010 0x7fabc6125ade in __clone (/lib/x86_64-linux-gnu/libc.so.6+0xfbade)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0xa4255) in g_mutex_lock
Thread T1 (TriggerBox Work) created by T0 (ArdourGUI) here:
    #0 0x7fabcce552a2 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:214
    0000001 0x7fabc7cd83cd in pthread_create_and_store(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, unsigned long*, void* (*)(void*), void*, unsigned int) ../libs/pbd/pthread_utils.cc:231
    #2 0x7fabcc00d58d in ARDOUR::TriggerBoxThread::TriggerBoxThread() ../libs/ardour/triggerbox.cc:5689
    #3 0x7fabcbfeb93b in ARDOUR::TriggerBox::init() ../libs/ardour/triggerbox.cc:3631
    0000004 0x7fabcb28d2b9 in ARDOUR::init(bool, char const*, bool) ../libs/ardour/globals.cc:646
    0000005 0x560642295293 in main ../gtk2_ardour/main.cc:421
    #6 0x7fabc604dd79 in __libc_start_main ../csu/libc-start.c:308

==2416407==ABORTING

diff --git a/libs/ardour/triggerbox.cc b/libs/ardour/triggerbox.cc
index bf95500cb1..e50c38918e 100644
--- a/libs/ardour/triggerbox.cc
+++ b/libs/ardour/triggerbox.cc
@@ -3085,6 +3085,9 @@ MIDITrigger::set_region_in_worker_thread (std::shared_ptr<Region> r)
        set_name (mr->name());
 
        _model = mr->model();
+       if (!_model) {
+               return -1;
+       }
        _model->ContentsChanged.connect_same_thread (content_connection, std::bind (&MIDITrigger::model_contents_changed, this));
 
        _play_start = _region->start().beats ();