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Re: [Qemu-devel] [PATCH] gdbstub: do not restart crashed guest
From: |
Luiz Capitulino |
Subject: |
Re: [Qemu-devel] [PATCH] gdbstub: do not restart crashed guest |
Date: |
Thu, 30 May 2013 08:43:58 -0400 |
On Thu, 30 May 2013 13:55:50 +0200
Laszlo Ersek <address@hidden> wrote:
> On 05/30/13 13:20, Paolo Bonzini wrote:
> > If a guest has crashed with an internal error or similar, detaching
> > gdb (or any other debugger action) should not restart it.
> >
> > Cc: Jan Kiszka <address@hidden>
> > Signed-off-by: Paolo Bonzini <address@hidden>
> > ---
> > gdbstub.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/gdbstub.c b/gdbstub.c
> > index e80e1d3..90e54cb 100644
> > --- a/gdbstub.c
> > +++ b/gdbstub.c
> > @@ -371,7 +371,9 @@ static inline void gdb_continue(GDBState *s)
> > #ifdef CONFIG_USER_ONLY
> > s->running_state = 1;
> > #else
> > - vm_start();
> > + if (runstate_check(RUN_STATE_DEBUG)) {
> > + vm_start();
> > + }
> > #endif
> > }
> >
> >
>
> I sought to check the gdb_continue() call sites, and uses of
> RUN_STATE_DEBUG. Seems reasonable.
>
> Reviewed-by: Laszlo Ersek <address@hidden>
>
> (
> FWIW I wonder why in commit ad02b96a Luiz allowed DEBUG -> SUSPENDED. As
> far as I understand, when the debugger is attached, the guest is not
> running, hence it can't go directly to RUN_STATE_SUSPENDED. Maybe due to
> a concurrent monitor command?
I honestly don't remember if I took into account the explanation you gave
below. You're right that a stopped guest can't suspend.
>
> Technically it does seem possible; from main_loop_should_exit():
>
> if (qemu_debug_requested()) {
> vm_stop(RUN_STATE_DEBUG);
> }
> if (qemu_suspend_requested()) {
> qemu_system_suspend();
> }
>
> Both requests could become pending during one iteration of the loop, and
> the next iteration will see both of them. OK.
> )
>
> Laszlo
>