(gdb) bt
#0  0x00007fffedd6678d in _int_free (av=0x7fffee0aac00 <main_arena>, p=0x137db50, have_lock=0) at malloc.c:3914
#1  0x00007fffedd6a89c in __GI___libc_free (mem=<optimized out>) at malloc.c:2950
#2  0x00007ffff4eb578b in g_string_free () from /opt/ardour4/lib/libglib-2.0.so.0
#3  0x00007ffff4ea911a in ?? () from /opt/ardour4/lib/libglib-2.0.so.0
#4  0x00007ffff4eaa3f8 in g_scanner_get_next_token () from /opt/ardour4/lib/libglib-2.0.so.0
#5  0x00007ffff44e7c62 in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#6  0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#7  0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#8  0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#9  0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#10 0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#11 0x00007ffff44e7e6c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#12 0x00007ffff44e7da0 in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#13 0x00007ffff44e846d in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#14 0x00007ffff44ec38d in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#15 0x00007ffff44ed90c in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#16 0x00007ffff44eddb4 in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#17 0x00007ffff436a48f in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#18 0x00007ffff44edbca in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#19 0x00007ffff44eddb4 in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#20 0x00007ffff44ef1f7 in ?? () from /opt/ardour4/lib/libgtk-x11-2.0.so.0
#21 0x00007ffff519aa05 in g_closure_invoke () from /opt/ardour4/lib/libgobject-2.0.so.0
#22 0x00007ffff51abca1 in ?? () from /opt/ardour4/lib/libgobject-2.0.so.0
#23 0x00007ffff51b5b81 in g_signal_emit_valist () from /opt/ardour4/lib/libgobject-2.0.so.0
#24 0x00007ffff51b5f02 in g_signal_emit () from /opt/ardour4/lib/libgobject-2.0.so.0
#25 0x00007ffff519ecd5 in ?? () from /opt/ardour4/lib/libgobject-2.0.so.0
#26 0x00007ffff519e708 in ?? () from /opt/ardour4/lib/libgobject-2.0.so.0
#27 0x00007ffff51a33fc in g_object_set_property () from /opt/ardour4/lib/libgobject-2.0.so.0
#28 0x0000000000b2adcc in ?? ()
#29 0x0000000000b2af6d in ?? ()
#30 0x000000000052ae82 in ?? ()
#31 0x0000000000b21c20 in ?? ()
#32 0x0000000000b220de in ?? ()
#33 0x00000000004cc71c in ?? ()
#34 0x000000000048a705 in ?? ()
#35 0x00007fffedd06a40 in __libc_start_main (main=0x48a300, argc=1, argv=0x7fffffffd3c8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffd3b8) at libc-start.c:289
#36 0x0000000000494894 in ?? ()