#0  __GI___pthread_mutex_lock (mutex=0x0) at pthread_mutex_lock.c:50
        __PRETTY_FUNCTION__ = "__pthread_mutex_lock"
        type = <optimized out>
        id = <optimized out>
#1  0x40da2a70 in pthread_mutex_lock (mutex=<optimized out>) at forward.c:192
        __p = <optimized out>
#2  0x404eb532 in __gthread_mutex_lock (__mutex=0x0) at /usr/include/arm-linux-gnueabihf/c++/4.8/bits/gthr-default.h:748
No locals.
#3  lock (this=0x0) at /usr/include/c++/4.8/mutex:134
No locals.
#4  lock_guard (__m=..., this=<synthetic pointer>) at /usr/include/c++/4.8/mutex:414
No locals.
#5  mir::client::DisplayConfiguration::copy_to_client (this=0x0) at /build/buildd/mir-0.0.15+13.10.20131014/src/client/display_configuration.cpp:146
        lk = {_M_device = @0x0}
        new_config = <optimized out>
#6  0x404ed6a8 in MirConnection::create_copy_of_display_config (this=0x1db1a00) at /build/buildd/mir-0.0.15+13.10.20131014/src/client/mir_connection.cpp:363
        lock = {_M_device = @0x1db1a04}
#7  0x404ec286 in mir_connection_create_display_config (connection=<optimized out>) at /build/buildd/mir-0.0.15+13.10.20131014/src/client/mir_client_library.cpp:283
No locals.
#8  0x404ec294 in mir_connection_get_display_info (connection=<optimized out>, display_info=0x1dae1d8) at /build/buildd/mir-0.0.15+13.10.20131014/src/client/mir_client_library.cpp:295
        config = <optimized out>
#9  0x400df388 in ua_ui_display_new_with_index (index=<optimized out>) at /build/buildd/platform-api-0.19+13.10.20131015.1/src/ubuntu/mirclient/ubuntu_application_api_mirclient.cpp:164
        instance = 0x400f7340 <(anonymous namespace)::global_mir_instance()::instance>
        display = 0x1dae1d8
#10 0x401ce1f6 in QUbuntuBaseScreen::~QUbuntuBaseScreen (this=0x1dae418, __in_chrg=<optimized out>) at screen.cc:121
No locals.
#11 0x40905432 in QObject::QObject (this=0x1daf848, parent=0x1dae428) at kernel/qobject.cpp:680
        d = 0x1dae418
#12 0x401cca0a in qRound (d=0.434294462) at /usr/include/qt5/QtCore/qglobal.h:488
No locals.
#13 QUbuntuScreen::densityPixelToPixel (this=0x0, value=0) at screen.cc:140
No locals.
#14 0x40059000 in ?? () from /tmp/apport_sandbox_PufhvL/lib/ld-linux-armhf.so.3
Cannot access memory at address 0x1
No symbol table info available.
#15 0x40059000 in ?? () from /tmp/apport_sandbox_PufhvL/lib/ld-linux-armhf.so.3
Cannot access memory at address 0x1
No symbol table info available.
Backtrace stopped: previous frame identical to this frame (corrupt stack?)