From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1Kxp7e-0007u3-Qp
	for qemu-devel@nongnu.org; Wed, 05 Nov 2008 15:37:02 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1Kxp7c-0007pu-B9
	for qemu-devel@nongnu.org; Wed, 05 Nov 2008 15:37:01 -0500
Received: from [199.232.76.173] (port=57436 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Kxp7c-0007pJ-4K
	for qemu-devel@nongnu.org; Wed, 05 Nov 2008 15:37:00 -0500
Received: from qw-out-1920.google.com ([74.125.92.145]:51357)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <anthony@codemonkey.ws>) id 1Kxp7b-0003UO-Pc
	for qemu-devel@nongnu.org; Wed, 05 Nov 2008 15:36:59 -0500
Received: by qw-out-1920.google.com with SMTP id 5so166984qwc.4
	for <qemu-devel@nongnu.org>; Wed, 05 Nov 2008 12:36:58 -0800 (PST)
Message-ID: <491203E7.50607@codemonkey.ws>
Date: Wed, 05 Nov 2008 14:36:55 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Re: [PATCH] Fix alarm_timer race with select - v3
References: <4911E5AA.1000408@siemens.com>	<f43fc5580811051035v15514fb7h7eb48b2c74511102@mail.gmail.com>
	<4911EE29.7040300@siemens.com>
In-Reply-To: <4911EE29.7040300@siemens.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Reply-To: qemu-devel@nongnu.org
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: qemu-devel@nongnu.org

Jan Kiszka wrote:
> Changing the default IO timeout to 5 s (#5578) made a race visible
> between the alarm_timer and select() in main_loop_wait(): If the timer
> fired before select was able to block, the full select() timeout could
> have been applied instead of returning immediately. Since #5578, this
> causes heavy problems to the Musicpal board emulation with stalls up to
> 5 s, but also with some older Linux guest kernels.
>
> The following patch introduces a pipe that is written to by
> host_alarm_handler and select()'ed in main_loop_wait(). This avoids
> prevents that select() blocks though a timer has fired and waits for
> processing.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
>   

Applied.  Thanks.

Regards,

Anthony Liguori