.
Thread 2 (process 14370):
#0  0x00002b9e9d8bd987 in pthread_cond_timedwait@@GLIBC_2.3.2 ()
   from /lib/libpthread.so.0
#1  0x00002b9e9c427515 in ?? () from /usr/lib/libqt-mt.so.3
#2  0x00002b9e9c4277de in QThread::sleep () from /usr/lib/libqt-mt.so.3
#3  0x000000000042ccbb in ?? ()
#4  0x00002b9e9c42803e in QThreadInstance::start ()
   from /usr/lib/libqt-mt.so.3
#5  0x00002b9e9d8b92a5 in start_thread () from /lib/libpthread.so.0
#6  0x00002b9e9e33361d in clone () from /lib/libc.so.6
#7  0x0000000000000000 in ?? ()
.
Thread 1 (process 14369):
#0  0x00002aaaaafc7aae in viaGetLock () from /usr/lib/dri/unichrome_dri.so
#1  0x00002aaaaafcbc9f in viaWaitIdle () from /usr/lib/dri/unichrome_dri.so
#2  0x00002aaaaafc809e in viaDestroyContext ()
   from /usr/lib/dri/unichrome_dri.so
#3  0x00002aaaaafc3b5a in ?? () from /usr/lib/dri/unichrome_dri.so
#4  0x00002b9e9cf1fe75 in ?? () from /usr/lib/libGL.so.1
#5  0x00002b9e9c710e41 in QGLContext::reset () from /usr/lib/libqt-mt.so.3
#6  0x00002b9e9c70ac27 in QGLContext::~QGLContext ()
   from /usr/lib/libqt-mt.so.3
#7  0x00002b9e9c70f442 in QGLWidget::setContext () from /usr/lib/libqt-mt.so.3
#8  0x0000000000459dcb in ?? ()
#9  0x000000000045bba2 in ?? ()
#10 0x00000000004145f6 in ?? ()
#11 0x00002b9e9e2818e4 in __libc_start_main () from /lib/libc.so.6
#12 0x0000000000414089 in ?? ()
#13 0x00007fff0ec6c718 in ?? ()
#14 0x0000000000000000 in ?? ()