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Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() fail
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure |
Date: |
Tue, 18 Feb 2014 10:05:04 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Feb 17, 2014 at 06:00:03PM +0100, Markus Armbruster wrote:
> Paolo Bonzini <address@hidden> writes:
>
> > Il 17/02/2014 16:44, Stefan Hajnoczi ha scritto:
> >> }
> >>
> >> +static void sigabrt_handler(int signo)
> >> +{
> >> + qtest_end();
> >> +}
> >> +
> >
> > void qtest_quit(QTestState *s)
> > {
> > int status;
> >
> > if (s->qemu_pid != -1) {
> > kill(s->qemu_pid, SIGTERM);
> > waitpid(s->qemu_pid, &status, 0);
> > }
> >
> > close(s->fd);
> > close(s->qmp_fd);
> > g_string_free(s->rx, true);
> > g_free(s);
> > }
> >
> > Not async-signal safe. You need to ignore the g_string_free and
> > g_free (perhaps even the closes) if calling from the sigabrt_handler.
>
> kill(), waitpid() and close() are all async-signal-safe.
>
> SIGABRT is normally synchronous enough: it's sent by abort(). But of
> course, nothing stops the user from kill -ABRT. Or GLib from calling
> abort() in some place where an attempt to reenter it crashes & burns.
> Not sure I'd care, but I'm pretty sure I don't care for freeing stuff on
> exit :)
Yes, SIGABRT is synchronous for all purposes. So the only danger is
that g_string_free() or g_free() could fail while we're in
g_assert(false). But they don't, which makes sense because they are
totally unrelated to g_assert() and therefore can handle re-entrancy.
In practice there is no issue and I've tested assertion failure with
glib 1.2.10.
Stefan
- [Qemu-devel] [PATCH 0/3] qtest: avoid pidfile and QEMU process leaks, Stefan Hajnoczi, 2014/02/17
- [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Stefan Hajnoczi, 2014/02/17
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Paolo Bonzini, 2014/02/17
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Markus Armbruster, 2014/02/17
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure,
Stefan Hajnoczi <=
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Markus Armbruster, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Paolo Bonzini, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Markus Armbruster, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Stefan Hajnoczi, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Paolo Bonzini, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Daniel P. Berrange, 2014/02/18
- Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Paolo Bonzini, 2014/02/18
Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert() failure, Markus Armbruster, 2014/02/17