[android] SIGTERM to server with connected client causes crash

The problem seems to be that we are getting a vsync callback after the HWCCommonDevice class has been destroyed (verified with debug prints in ~HWCCommonDevice() and vsync_hook()). Not sure how to solve this (can we unregister the hooks on HWCCommonDevice destruction, does vsync_hook need to handle a destroyed "self"?), so leaving it to our Android resident experts.

The best backtrace I could get is:

Thread 2 (Thread 0xb61563e0 (LWP 24473)):
#0 0xb69c88e6 in ?? () from /lib/arm-linux-gnueabihf/libc.so.6
#1 0xb69d705e in raise () from /lib/arm-linux-gnueabihf/libc.so.6
#2 0xb69d7d4e in abort () from /lib/arm-linux-gnueabihf/libc.so.6
#3 0xb6b89184 in __gnu_cxx::__verbose_terminate_handler() ()
   from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#4 0xb6b879b4 in ?? () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#5 0xb6b87a0a in std::terminate() () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#6 0xb6b88332 in __cxa_pure_virtual () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6
#7 0xb63fac0a in mir::graphics::android::HWCCommonDevice::notify_vsync (this=0xcc660)
    at /storage/work/mir/src/platform/graphics/android/hwc_common_device.cpp:85
#8 0xb63faa16 in (anonymous namespace)::vsync_hook (procs=0xcc66c)
    at /storage/work/mir/src/platform/graphics/android/hwc_common_device.cpp:38
#9 0xb6164bf8 in ?? ()

Yes, so the driver is calling the vsync hook after mir has instructed th driver to send no more vsync signals. Seems like a driver bug, looking at finding a way to work around.

Fix committed into lp:mir/devel at revision None, scheduled for release in mir, milestone Unknown

This bug was fixed in the package mir - 0.8.0+14.10.20141010-0ubuntu1

---------------
mir (0.8.0+14.10.20141010-0ubuntu1) utopic; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 0.8.0 (https://launchpad.net/mir/+milestone/0.8.0)
    - Enhancements:
      . Less sensitivity to ABI breaks - many headers unused by external
        projects are now hidden and not installed by -dev packaes. If you
        require any headers that are missing, just ask.
      . Touchspots: --enable-touchspots to servers; visually shows touch
        locations (warning: This affects performance LP: #1373692).
      . Client performance reporting: Any Mir client can now get accurate
        performance information (frame rate, render time, buffer lag etc)
        logged to stdout. Just set env MIR_CLIENT_PERF_REPORT=log
      . Further improved touch responsiveness, with less lag and smoother
        scrolling (so long as you don't enable touchspots).
      . Slightly faster builds using precompiled headers.
      . Turn hardware overlays on by default. When in use, this halves the
        CPU usage of a Mir server. Already enabled in unity-system-compositor.
      . More scripting to detect ABI breaks.
      . Improved src/ tree consistency (renamed "src/shared" to "src/common").
      . Improved fatal signal design: Changed from SIGTERM to SIGHUP delivered
        to clients on unexpected server disconnection.
      . Improved library/package design to allow concurrent installations
        of different Mir versions without conflicts.
      . Fd reception code is now common to client and server.
    - ABI summary: Servers need rebuilding, but clients do not;
      . Mirclient ABI unchanged at 8
      . Mircommon ABI bumped to 2
      . Mirplatform ABI bumped to 3
      . Mirserver ABI bumped to 26
    - API changes between Mir 0.7 and 0.8:
      . Lots of headers removed from the public SDK! We have only hidden
        headers not known to be used by any known projects. Please let us
        know if anything is missing - https://bugs.launchpad.net/mir/+filebug
      . graphics::Platform - interface changed significantly.
      . Lots of server API changes to support touchspots.
      . File descriptors now passed as type Fd instead of int32_t.
    - Bug fixes:
      . [regression] Mir deb packages with versioned names cannot be installed
        simultaneously any more (LP: #1293944)
      . A frozen client can hang the whole server (LP: #1350207)
      . QtMir FTBFS: fatal error: mir/input/input_channel.h: No such file or
        directory (LP: #1365934)
      . [regression] platform-api fails to build against Mir 0.8 (LP: #1368354)
      . Mir FTBFS with gcc 4.9.1-14 (utopic update):
        auto_unblock_thread.h:44:46: error: no matching function for call to
        ‘std::thread::thread(<brace-enclosed initializer list>)’ (LP: #1369389)
      . [regression] Compositing is jerky and stutters during touch events
        (LP: #1372850)
      . unit test fails: AndroidInputReceiverSetup.slow_raw_input_doesnt_cause_
        frameskipping (LP: #1373826)
      . intermittent hang in TestClientInput (LP: #1338612)
      . TestClientInput.scene_obscure_mo...

This bug was fixed in the package mir - 0.8.0+14.10.20141005-0ubuntu1

---------------
mir (0.8.0+14.10.20141005-0ubuntu1) 14.09; urgency=medium

  [ Daniel van Vugt ]
  * New upstream release 0.8.0 (https://launchpad.net/mir/+milestone/0.8.0)
    - Enhancements:
      . Less sensitivity to ABI breaks - many headers unused by external
        projects are now hidden and not installed by -dev packaes. If you
        require any headers that are missing, just ask.
      . Touchspots: --enable-touchspots to servers; visually shows touch
        locations (warning: This affects performance LP: #1373692).
      . Client performance reporting: Any Mir client can now get accurate
        performance information (frame rate, render time, buffer lag etc)
        logged to stdout. Just set env MIR_CLIENT_PERF_REPORT=log
      . Further improved touch responsiveness, with less lag and smoother
        scrolling (so long as you don't enable touchspots).
      . Slightly faster builds using precompiled headers.
      . Turn hardware overlays on by default. When in use, this halves the
        CPU usage of a Mir server. Already enabled in unity-system-compositor.
      . More scripting to detect ABI breaks.
      . Improved src/ tree consistency (renamed "src/shared" to "src/common").
      . Improved fatal signal design: Changed from SIGTERM to SIGHUP delivered
        to clients on unexpected server disconnection.
      . Improved library/package design to allow concurrent installations
        of different Mir versions without conflicts.
      . Fd reception code is now common to client and server.
    - ABI summary: Servers need rebuilding, but clients do not;
      . Mirclient ABI unchanged at 8
      . Mircommon ABI bumped to 2
      . Mirplatform ABI bumped to 3
      . Mirserver ABI bumped to 26
    - API changes between Mir 0.7 and 0.8:
      . Lots of headers removed from the public SDK! We have only hidden
        headers not known to be used by any known projects. Please let us
        know if anything is missing - https://bugs.launchpad.net/mir/+filebug
      . graphics::Platform - interface changed significantly.
      . Lots of server API changes to support touchspots.
      . File descriptors now passed as type Fd instead of int32_t.
    - Bug fixes:
      . [regression] Mir deb packages with versioned names cannot be installed
        simultaneously any more (LP: #1293944)
      . A frozen client can hang the whole server (LP: #1350207)
      . QtMir FTBFS: fatal error: mir/input/input_channel.h: No such file or
        directory (LP: #1365934)
      . [regression] platform-api fails to build against Mir 0.8 (LP: #1368354)
      . Mir FTBFS with gcc 4.9.1-14 (utopic update):
        auto_unblock_thread.h:44:46: error: no matching function for call to
        ‘std::thread::thread(<brace-enclosed initializer list>)’ (LP: #1369389)
      . [regression] Compositing is jerky and stutters during touch events
        (LP: #1372850)
      . unit test fails: AndroidInputReceiverSetup.slow_raw_input_doesnt_cause_
        frameskipping (LP: #1373826)
      . intermittent hang in TestClientInput (LP: #1338612)
      . TestClientInput.scene_obscure_mot...