From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:40609)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1WFloy-0004IU-8f
	for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:39:00 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1WFlop-00006o-SE
	for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:38:52 -0500
Received: from mail-wg0-x234.google.com ([2a00:1450:400c:c00::234]:48025)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1WFlop-00006e-LI
	for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:38:43 -0500
Received: by mail-wg0-f52.google.com with SMTP id b13so3384263wgh.7
	for <qemu-devel@nongnu.org>; Tue, 18 Feb 2014 06:38:42 -0800 (PST)
Date: Tue, 18 Feb 2014 15:38:39 +0100
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20140218143839.GA15348@stefanha-thinkpad.redhat.com>
References: <1392651898-16749-1-git-send-email-stefanha@redhat.com>
	<1392651898-16749-4-git-send-email-stefanha@redhat.com>
	<878ut9u1k4.fsf@blackfin.pond.sub.org>
	<87sirgivqr.fsf@blackfin.pond.sub.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <87sirgivqr.fsf@blackfin.pond.sub.org>
Subject: Re: [Qemu-devel] [PATCH 3/3] qtest: kill QEMU process on g_assert()
 failure
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Markus Armbruster <armbru@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Andreas Faerber <afaerber@suse.de>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>, Anthony Liguori <aliguori@amazon.com>

On Tue, Feb 18, 2014 at 11:02:52AM +0100, Markus Armbruster wrote:
> Markus Armbruster <armbru@redhat.com> writes:
> 
> > Stefan Hajnoczi <stefanha@redhat.com> writes:
> >
> >> The QEMU process stays running if the test case fails.  This patch fixes
> >> the leak by installing a SIGABRT signal handler which invokes
> >> qtest_end().
> >>
> >> In order to make that work for assertion failures during qtest_init(),
> >> we need to initialize QTestState fields including file descriptors and
> >> pids carefully.  qtest_quit() is then safe to call even during
> >> qtest_init().
> >>
> >> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> >> ---
> >>  tests/libqtest.c | 29 ++++++++++++++++++++++++++---
> >>  1 file changed, 26 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/tests/libqtest.c b/tests/libqtest.c
> >> index 8b2b2d7..09a0481 100644
> >> --- a/tests/libqtest.c
> >> +++ b/tests/libqtest.c
> >> @@ -44,6 +44,7 @@ struct QTestState
> >>      bool irq_level[MAX_IRQ];
> >>      GString *rx;
> >>      pid_t qemu_pid;  /* our child QEMU process */
> >> +    struct sigaction sigact_old; /* restored on exit */
> >>  };
> >>  
> >>  #define g_assert_no_errno(ret) do { \
> >> @@ -88,6 +89,11 @@ static int socket_accept(int sock)
> >>      return ret;
> >>  }
> >>  
> >> +static void sigabrt_handler(int signo)
> >> +{
> >> +    qtest_end();
> 
> Don't you have to re-raise SIGABRT here, to actually terminate the
> process?

No.  POSIX says:

  RETURN VALUE
       The abort() function shall not return.

(BTW the way to avoid that is using longjmp.)

The Linux man page is more explicit:

  If  the  SIGABRT  signal  is ignored, or caught by a handler that returns,
  the abort() function will still terminate the process.  It does this by
  restoring the default disposition for  SIGABRT and then raising the signal
  for a second time.