From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51815) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9DHF-0001Uq-6e for qemu-devel@nongnu.org; Thu, 08 Jan 2015 08:37:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y9DHA-0003AY-Sv for qemu-devel@nongnu.org; Thu, 08 Jan 2015 08:37:29 -0500 Received: from vps01.wiesinger.com ([46.36.37.179]:40879) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y9DHA-0002yj-Ec for qemu-devel@nongnu.org; Thu, 08 Jan 2015 08:37:24 -0500 Received: from wiesinger.com (wiesinger.com [62.178.19.14]) by vps01.wiesinger.com (Postfix) with ESMTP id C175C9F1E2 for ; Thu, 8 Jan 2015 14:36:11 +0100 (CET) Received: from [192.168.0.14] ([192.168.0.14]) (authenticated bits=0) by wiesinger.com (8.14.9/8.14.9) with ESMTP id t08Da1ON015200 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 8 Jan 2015 14:36:01 +0100 Message-ID: <54AE87C1.2060907@wiesinger.com> Date: Thu, 08 Jan 2015 14:36:01 +0100 From: Gerhard Wiesinger MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Fedora FC21 - Bug: 100% CPU and hangs in gettimeofday(&tp, NULL); forever List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hello, After upgrading my KVM environment from Fedora 20 to Fedora 21 up2date (hosts and guests, Intel CPU) I've the following problem: 1.) On the database VM PostgresSQL e.g. 2 processes hang with 100% cpu 2.) On the monitoring VM Munin/RRDtool also hangs with 100% cpu Killing of processes is not possible, only reboot helps. But I nailed it down to the following: yum install strace strace -y -p339 Process 339 attached # no system calls here ^CProcess 339 detached Going deeper: yum --enablerepo fedora-debuginfo,updates-debuginfo install gdb postgresql-debuginfo gdb postgres 339 (gdb) bt #0 0x00007fffffbf8ff8 in gettimeofday () #1 0x00000000006d425e in GetCurrentTimestamp () at timestamp.c:1274 (gdb) frame 1 #1 0x00000000006d425e in GetCurrentTimestamp () at timestamp.c:1274 1274 gettimeofday(&tp, NULL); (same on second process here) Quitting and reattaching gdb also hangs here, so gettimeofday takes 100% CPU and never ends! Therefore I guess this is a problem either in the Linux kernel or in QEMU/KVM. It might be the case that something changed in timer handling or some default changed here. VMs are time syncrhonized with NTP so this might also be a problem that the syscall hangs here. Workaround when it happens: reboot .... Any further ideas? Thank you. Ciao, Gerhard