Comment 7 for bug 1380848

Just got another unity8 crash and this time system-settings maxing the cpu. Here is the thread dump. It appears it's in a tight loop spawing and exiting threads:

(gdb) bt
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) t a a bt

Thread 15 (Thread 0xb2297450 (LWP 4318)):
Cannot access memory at address 0x0
#0 0xb442c840 in ?? ()
Cannot access memory at address 0x0
#1 0xb444029c in ?? ()
Cannot access memory at address 0x0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 14 (Thread 0xb2507b40 (LWP 4319)):
#0 0xb5e11b76 in ?? () from /lib/arm-linux-gnueabihf/librt.so.1
#1 0xb5e11be2 in ?? () from /lib/arm-linux-gnueabihf/librt.so.1
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 13 (Thread 0xb18ff450 (LWP 4320)):
#0 0xb6199554 in __libc_do_syscall () from /lib/arm-linux-gnueabihf/libpthread.so.0
#1 0xb6195192 in pthread_cond_wait@@GLIBC_2.4 () from /lib/arm-linux-gnueabihf/libpthread.so.0
Cannot access memory at address 0x3000000
#2 0xb235e0a8 in ?? ()
Cannot access memory at address 0x3000000
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 12 (Thread 0xb10ff450 (LWP 4321)):
#0 0xb6199554 in __libc_do_syscall () from /lib/arm-linux-gnueabihf/libpthread.so.0
#1 0xb6195192 in pthread_cond_wait@@GLIBC_2.4 () from /lib/arm-linux-gnueabihf/libpthread.so.0
Cannot access memory at address 0x3000000
#2 0xb235e0a8 in ?? ()
Cannot access memory at address 0x3000000
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 11 (Thread 0xb08ff450 (LWP 4322)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 10 (Thread 0xae9bb450 (LWP 4328)):
#0 0xb6242712 in epoll_wait () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb3d20422 in ?? () from /usr/lib/arm-linux-gnueabihf/libdbus-cpp.so.4
#2 0xb3d222be in ?? () from /usr/lib/arm-linux-gnueabihf/libdbus-cpp.so.4
#3 0xb3d2268e in ?? () from /usr/lib/arm-linux-gnueabihf/libdbus-cpp.so.4
---Type <return> to continue, or q <return> to quit---
#4 0xb3d0b92c in core::dbus::Bus::run() () from /usr/lib/arm-linux-gnueabihf/libdbus-cpp.so.4
#5 0xb634f360 in ?? () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#6 0xb6191f98 in start_thread () from /lib/arm-linux-gnueabihf/libpthread.so.0
#7 0xb624222c in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 9 (Thread 0xadf2e450 (LWP 4332)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 8 (Thread 0xad433450 (LWP 4335)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 7 (Thread 0xacc33450 (LWP 4336)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 6 (Thread 0xabd88450 (LWP 4337)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 5 (Thread 0xab25d450 (LWP 4342)):
#0 0xb6231816 in sched_yield () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb3bd6582 in ?? () from /usr/lib/arm-linux-gnueabihf/libmircommon.so.2
#2 0xb634f360 in ?? () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#3 0xb6191f98 in start_thread () from /lib/arm-linux-gnueabihf/libpthread.so.0
#4 0xb624222c in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
---Type <return> to continue, or q <return> to quit---

Thread 4 (Thread 0xaaa1d450 (LWP 4343)):
#0 0xb6199554 in __libc_do_syscall () from /lib/arm-linux-gnueabihf/libpthread.so.0
#1 0xb6195192 in pthread_cond_wait@@GLIBC_2.4 () from /lib/arm-linux-gnueabihf/libpthread.so.0
#2 0xb6bbc05c in QWaitCondition::wait(QMutex*, unsigned long) ()
   from /usr/lib/arm-linux-gnueabihf/libQt5Core.so.5
#3 0xb670318c in ?? () from /usr/lib/arm-linux-gnueabihf/libQt5Quick.so.5
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 3 (Thread 0xaa21d450 (LWP 4344)):
#0 0xb6199554 in __libc_do_syscall () from /lib/arm-linux-gnueabihf/libpthread.so.0
#1 0xb6195192 in pthread_cond_wait@@GLIBC_2.4 () from /lib/arm-linux-gnueabihf/libpthread.so.0
Cannot access memory at address 0x3000000
#2 0xb235e0a8 in ?? ()
Cannot access memory at address 0x3000000
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 2 (Thread 0xa99b7450 (LWP 4406)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 1 (Thread 0xb6f03000 (LWP 4304)):
#0 0xb623baa2 in poll () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb5e5c0c0 in ?? () from /lib/arm-linux-gnueabihf/libglib-2.0.so.0
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
(gdb) continue
Continuing.
Cannot access memory at address 0x0
[New Thread 0xa85a7450 (LWP 8483)]
[Thread 0xa85a7450 (LWP 8483) exited]
[New Thread 0xa85a7450 (LWP 8488)]
[Thread 0xa85a7450 (LWP 8488) exited]
[New Thread 0xa85a7450 (LWP 8501)]
[Thread 0xa85a7450 (LWP 8501) exited]
[New Thread 0xa85a7450 (LWP 8506)]
[Thread 0xa85a7450 (LWP 8506) exited]
[New Thread 0xa85a7450 (LWP 8511)]
[Thread 0xa85a7450 (LWP 8511) exited]
[New Thread 0xa85a7450 (LWP 8515)]
[Thread 0xa85a7450 (LWP 8515) exited]
[New Thread 0xa85a7450 (LWP 8518)]
[Thread 0xa85a7450 (LWP 8518) exited]
[New Thread 0xa85a7450 (LWP 8522)]
[Thread 0xa85a7450 (LWP 8522) exited]
[New Thread 0xa85a7450 (LWP 8526)]
[Thread 0xa85a7450 (LWP 8526) exited]
[New Thread 0xa85a7450 (LWP 8530)]
[Thread 0xa85a7450 (LWP 8530) exited]
[New Thread 0xa85a7450 (LWP 8534)]
[Thread 0xa85a7450 (LWP 8534) exited]
[New Thread 0xa85a7450 (LWP 8540)]
[Thread 0xa85a7450 (LWP 8540) exited]
[New Thread 0xa85a7450 (LWP 8544)]
[Thread 0xa85a7450 (LWP 8544) exited]
[New Thread 0xa85a7450 (LWP 8548)]
[Thread 0xa85a7450 (LWP 8548) exited]
[New Thread 0xa85a7450 (LWP 8552)]
[Thread 0xa85a7450 (LWP 8552) exited]
[New Thread 0xa85a7450 (LWP 8556)]
[Thread 0xa85a7450 (LWP 8556) exited]
[New Thread 0xa85a7450 (LWP 8560)]
[Thread 0xa85a7450 (LWP 8560) exited]
[New Thread 0xa85a7450 (LWP 8564)]
[Thread 0xa85a7450 (LWP 8564) exited]
[New Thread 0xa85a7450 (LWP 8568)]
[Thread 0xa85a7450 (LWP 8568) exited]
[New Thread 0xa85a7450 (LWP 8572)]
[Thread 0xa85a7450 (LWP 8572) exited]
[New Thread 0xa85a7450 (LWP 8576)]
[Thread 0xa85a7450 (LWP 8576) exited]
[New Thread 0xa85a7450 (LWP 8584)]
[Thread 0xa85a7450 (LWP 8584) exited]
[New Thread 0xa85a7450 (LWP 8588)]
[Thread 0xa85a7450 (LWP 8588) exited]
[New Thread 0xa85a7450 (LWP 8592)]
[Thread 0xa85a7450 (LWP 8592) exited]
[New Thread 0xa85a7450 (LWP 8596)]
[Thread 0xa85a7450 (LWP 8596) exited]
[New Thread 0xa85a7450 (LWP 8600)]
[Thread 0xa85a7450 (LWP 8600) exited]
[New Thread 0xa85a7450 (LWP 8604)]
[Thread 0xa85a7450 (LWP 8604) exited]
[New Thread 0xa85a7450 (LWP 8608)]
[Thread 0xa85a7450 (LWP 8608) exited]
[New Thread 0xa85a7450 (LWP 8612)]
[Thread 0xa85a7450 (LWP 8612) exited]
[New Thread 0xa85a7450 (LWP 8616)]
[Thread 0xa85a7450 (LWP 8616) exited]
[New Thread 0xa85a7450 (LWP 8620)]
[Thread 0xa85a7450 (LWP 8620) exited]
[New Thread 0xa85a7450 (LWP 8624)]
[Thread 0xa85a7450 (LWP 8624) exited]
[New Thread 0xa85a7450 (LWP 8628)]
[Thread 0xa85a7450 (LWP 8628) exited]
[New Thread 0xa85a7450 (LWP 8632)]
[Thread 0xa85a7450 (LWP 8632) exited]
[New Thread 0xa85a7450 (LWP 8636)]
[Thread 0xa85a7450 (LWP 8636) exited]
[New Thread 0xa85a7450 (LWP 8640)]
....
[goes on indefiinitely]