From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1IjMCE-0004iE-1j
	for qemu-devel@nongnu.org; Sat, 20 Oct 2007 17:49:26 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1IjMCC-0004hw-Oc
	for qemu-devel@nongnu.org; Sat, 20 Oct 2007 17:49:25 -0400
Received: from [199.232.76.173] (helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1IjMCC-0004hs-Ld
	for qemu-devel@nongnu.org; Sat, 20 Oct 2007 17:49:24 -0400
Received: from hall.aurel32.net ([88.191.38.19])
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <aurelien@aurel32.net>)
	id 1IjMCC-0007YH-9s
	for qemu-devel@nongnu.org; Sat, 20 Oct 2007 17:49:24 -0400
Message-ID: <471A77D9.8030008@aurel32.net>
Date: Sat, 20 Oct 2007 23:49:13 +0200
From: Aurelien Jarno <aurelien@aurel32.net>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] I got a kernel booted under qemu-system-ppc !
References: <200710181912.57825.rob@landley.net>	<20071019151916.GA17481@hall.aurel32.net>	<1192815587.11576.32.camel@jma4.dev.netgem.com>	<20071019193925.GA30604@hall.aurel32.net>	<471A0F52.9050206@aurel32.net>
	<471A1585.1060206@aurel32.net>
In-Reply-To: <471A1585.1060206@aurel32.net>
Content-Type: text/plain; charset=ISO-8859-15
Content-Transfer-Encoding: 8bit
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
Cc: Jocelyn Mayer <l_indien@magic.fr>, Milton Miller <miltonm@bga.com>

Aurelien Jarno a écrit :
> Aurelien Jarno a écrit :
>> Aurelien Jarno a écrit :
>>
>>> I have used QEMU CVS with a Debian Sid image. It basically works, I am
>>> even able to login via SSH, but I have noticed two problems:
>>>
>>> - Some process hang, stay into "D" state and become unkillable. It seems
>>>   it can happen to all processes, but it is always reproducible with
>>>   uptime or top. I still don't know if it is a problem of the kernel or
>>>   if it comes from the emulation.
>> This problem arise when using floating point instructions. It can be
>> easily triggered by running the following testcase:
>>
>> #include <stdio.h>
>>
>> int main()
>> {
>>         double a = 1.34;
>>         printf("%.2f", a);
>>         return 0;
>> }
>>
> 
> This is actually not enough to trigger the bug. The testcase works if
> the bug has already been trigger in another process before, for example
> uptime.
> 

I finally found a testcase that trigger the bug in any case:

#include <stdio.h>

int main()
{
	printf("%d %f\n", 7, 0.40);
	return 0;
}

The bug could also be trigger with sprintf(), so this is not directly
related to I/O. It happens when printing an integer followed by a float,
even when the two are printed in two different calls to printf().

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net