(gdb) bt
#0  syscall () at ../sysdeps/unix/sysv/linux/arm/syscall.S:37
#1  0xb63cfe12 in _q_futex (op=0, val=3, timeout=0x0, addr=<optimized out>)
    at thread/qmutex_linux.cpp:146
#2  lockInternal_helper<false> (timeout=-1, elapsedTimer=0x0, d_ptr=...)
    at thread/qmutex_linux.cpp:187
#3  QBasicMutex::lockInternal (this=this@entry=0x1f0d45c)
    at thread/qmutex_linux.cpp:203
#4  0xb63cfeb6 in lock (this=0x1f0d45c) at thread/qmutex.h:59
#5  lock (timeout=-1, this=0x1f0d450) at thread/qmutex.cpp:620
#6  QMutex::lock (this=this@entry=0x1f0d58c) at thread/qmutex.cpp:215
#7  0xb6007586 in QDBusMutexLocker (m=0x1f0d58c, s=0x1f0d568, 
    a=ToggleWatchAction, this=<synthetic pointer>) at qdbusthreaddebug_p.h:183
#8  QDBusDispatchLocker (s=0x1f0d568, a=ToggleWatchAction, 
    this=<synthetic pointer>) at qdbusthreaddebug_p.h:198
#9  qDBusRealToggleWatch (d=0x1f0d568, watch=0x1f0e600, fd=48)
    at qdbusintegrator.cpp:346
#10 0xb5baf8f6 in ?? () from /lib/arm-linux-gnueabihf/libdbus-1.so.3
Backtrace stopped: previous frame identical to this frame (corrupt stack?)