From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:36620) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UZgEY-0002At-OO for qemu-devel@nongnu.org; Tue, 07 May 2013 07:39:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UZgEV-0000Vv-T9 for qemu-devel@nongnu.org; Tue, 07 May 2013 07:39:02 -0400 Received: from gmplib-02.nada.kth.se ([130.237.222.242]:55748 helo=shell.gmplib.org) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UZgEV-0000Vq-N8 for qemu-devel@nongnu.org; Tue, 07 May 2013 07:38:59 -0400 From: Torbjorn Granlund Sender: tg@gmplib.org Date: Tue, 07 May 2013 13:38:57 +0200 Message-ID: <8661yvqasu.fsf@shell.gmplib.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] Reporting Heisenbugs in qemu List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org I am trying to use qemu to 1. cover more of the assembly code in GMP 2. check configuration logic of GMP but I am not as successful as I would like to be. The 2nd table of http://gmplib.org/devel/testsystems.html shows all emulated systems I am using, most of which are qemu-based. Unfortunately, several of the qemu-based systems experience intermittent but common segfaults: 1. Linux mips64eb 2.6.32-5-5kc-malta #1 Sun Sep 23 12:29:36 UTC 2012 mips64= GNU/Linux 2. Linux mips64el 2.6.32-5-5kc-malta #1 Fri Feb 15 21:38:11 UTC 2013 mips64= GNU/Linux 3. Linux kick.gmplib.org 2.6.18-6-sparc32 #1 Sat Dec 27 09:13:12 UTC 2008 s= parc GNU/Linux An example of a failure is: gmp/tests/cxx/t-ops2.cc: In function 'void checkz()': gmp/tests/cxx/t-ops2.cc:86: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See for instructions. For Debian GNU/Linux specific bug reporting instructions, see . The bug is not reproducible, so it is likely a hardware or OS problem. (This was from the sparc32 system.) rootrem.c: In function 'mpn_rootrem_internal': rootrem.c:120:1: internal compiler error: Segmentation fault Please submit a full bug report, with preprocessed source if appropriate. See for instructions. The bug is not reproducible, so it is likely a hardware or OS problem. (From the mips64eb system.) I am aware of that these systems don't exactly use the kernel-of-the-week. Newer kernels I have tried cause non-boot. (I don't think I've tried any newer sparc kernel, as building that would require a stable sparc system...) I realise that linux might have been debugged until it works on real hardware, but that qemu might trigger untested linux execution paths. Yesterday, I disabled GMP testing on these qemu systems, as I got tired of the many false alarms, and since GMP looked bad. Is there any hope that these qemu systems will become stable? Or aren't these problems qemu's fault? --=20 Torbj=C3=B6rn