(gdb) r
Starting program: /usr/bin/python /usr/bin/gnome-tweak-tool
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffee31f700 (LWP 7402)]
[New Thread 0x7fffedb1e700 (LWP 7403)]
Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 14: reading configurations from ~/.fonts.conf is deprecated.
[New Thread 0x7fffe6d04700 (LWP 7404)]
[New Thread 0x7fffe5c9b700 (LWP 7405)]
[New Thread 0x7fffe549a700 (LWP 7406)]
[New Thread 0x7fffe4c99700 (LWP 7407)]
[New Thread 0x7fffd2a1a700 (LWP 7408)]
[New Thread 0x7fffd2219700 (LWP 7409)]
INFO    : GSettings missing key org.gnome.nautilus.desktop (key computer-icon-visible)
[New Thread 0x7fffd1a18700 (LWP 7410)]
[New Thread 0x7fffd1217700 (LWP 7411)]
[Thread 0x7fffd2a1a700 (LWP 7408) exited]
[Thread 0x7fffe549a700 (LWP 7406) exited]
[Thread 0x7fffe5c9b700 (LWP 7405) exited]
[Thread 0x7fffe4c99700 (LWP 7407) exited]
[Thread 0x7fffd1217700 (LWP 7411) exited]
[Thread 0x7fffd1a18700 (LWP 7410) exited]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffee31f700 (LWP 7402)]
=> 0x7ffff7bcb1c0 <sem_post>:	mov    eax,DWORD PTR [rdi]
   0x7ffff7bcb1c2 <sem_post+2>:	cmp    eax,0x7fffffff
   0x7ffff7bcb1c7 <sem_post+7>:	je     0x7ffff7bcb1fc <sem_post+60>
   0x7ffff7bcb1c9 <sem_post+9>:	lea    esi,[rax+0x1]
   0x7ffff7bcb1cc <sem_post+12>:	lock cmpxchg DWORD PTR [rdi],esi
0x7fffee31ec48:	0x00542d69	0x00000000	0x01846d20	0x00000000
0x7fffee31ec58:	0xf63c2897	0x00007fff	0xf59e97f0	0x00007fff
sem_post () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_post.S:33
33	../nptl/sysdeps/unix/sysv/linux/x86_64/sem_post.S: No such file or directory.
(gdb) bt
#0  sem_post () at ../nptl/sysdeps/unix/sysv/linux/x86_64/sem_post.S:33
#1  0x0000000000542d69 in PyThread_release_lock (lock=0x0)
    at ../Python/thread_pthread.h:350
#2  0x00007ffff63c2897 in g_object_ref (_object=0x1846d20)
    at /build/buildd/glib2.0-2.38.1/./gobject/gobject.c:3069
#3  0x00007ffff59e9b70 in g_settings_backend_dispatch_signal (
    backend=backend@entry=0xc7a950, function_offset=function_offset@entry=0, 
    name=name@entry=0x7fffe8017d70 "/org/gnome/shell/extensions/transmission-daemon/latest-filter", data1=data1@entry=0x0, data1_copy=0x7ffff59e97f0 <pointer_id>, 
    data1_copy@entry=0x0, data1_free=0x7ffff59e9800 <pointer_ignore>, 
    data1_free@entry=0x0, data2=data2@entry=0x0)
    at /build/buildd/glib2.0-2.38.1/./gio/gsettingsbackend.c:329
#4  0x00007ffff59ea09a in g_settings_backend_changed (backend=0xc7a950, 
    key=0x7fffe8017d70 "/org/gnome/shell/extensions/transmission-daemon/latest-filter", origin_tag=0x0) at /build/buildd/glib2.0-2.38.1/./gio/gsettingsbackend.c:400
#5  0x00007fffee3252cb in ?? ()
   from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#6  0x00007ffff59fa405 in emit_signal_instance_in_idle_cb (data=0x7fffe0034180)
    at /build/buildd/glib2.0-2.38.1/./gio/gdbusconnection.c:3743
#7  0x00007ffff60f53b6 in g_main_dispatch (context=0xcec920)
    at /build/buildd/glib2.0-2.38.1/./glib/gmain.c:3065
#8  g_main_context_dispatch (context=context@entry=0xcec920)
    at /build/buildd/glib2.0-2.38.1/./glib/gmain.c:3641
---Type <return> to continue, or q <return> to quit---
#9  0x00007ffff60f5708 in g_main_context_iterate (context=context@entry=0xcec920, 
    block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/buildd/glib2.0-2.38.1/./glib/gmain.c:3712
#10 0x00007ffff60f57ac in g_main_context_iteration (context=0xcec920, may_block=1)
    at /build/buildd/glib2.0-2.38.1/./glib/gmain.c:3773
#11 0x00007fffee326a9d in ?? ()
   from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#12 0x00007ffff611a0f5 in g_thread_proxy (data=0xc842d0)
    at /build/buildd/glib2.0-2.38.1/./glib/gthread.c:798
#13 0x00007ffff7bc4f6e in start_thread (arg=0x7fffee31f700) at pthread_create.c:311
#14 0x00007ffff78ef9cd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113