[Qemu-commits] [qemu/qemu] edec47: main-loop: fix qemu_notify_event for aio_notify op...

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: edec47cfef96209987cb7922286cb384916aae02
      
https://github.com/qemu/qemu/commit/edec47cfef96209987cb7922286cb384916aae02
  Author: Paolo Bonzini <address@hidden>
  Date:   2015-07-27 (Mon, 27 Jul 2015)

  Changed paths:
    M main-loop.c

  Log Message:
  -----------
  main-loop: fix qemu_notify_event for aio_notify optimization

aio_notify can be optimized away, and in fact almost always will.  However,
qemu_notify_event is used in places where this is incorrect---most notably,
when handling SIGTERM.  When aio_notify is optimized away, it is possible that
QEMU enters a blocking ppoll immediately afterwards and stays there, without
reaching main_loop_should_exit().

Fix this by using a bottom half.  The bottom half can be optimized too, but
scheduling it is enough for the ppoll not to block.  The hang is thus avoided.

Reported-by: Peter Maydell <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Message-id: address@hidden
Signed-off-by: Peter Maydell <address@hidden>