From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan C. Bernauer" Subject: BUG: Guest lockup and 100% CPU load on host Date: Thu, 15 Jan 2009 23:10:25 +0100 Message-ID: <496FB451.3020002@t-online.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mailout10.t-online.de ([194.25.134.21]:60662 "EHLO mailout10.t-online.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933021AbZAOW1M (ORCPT ); Thu, 15 Jan 2009 17:27:12 -0500 Received: from [192.168.2.20] (unknown [192.168.2.20]) by codex (Postfix) with ESMTPSA id 6996C800078 for ; Thu, 15 Jan 2009 23:09:27 +0100 (CET) Sender: kvm-owner@vger.kernel.org List-ID: Hi, while I was trying to get pci passthrough to work without vt-d using the 1to1 mapping (it works ;), I stumbled upon a solid lock up of the guest. (Unpatched source shows the same behaviour) I see a strange look up of the guest OS with the following "features": - guest doesn't respond anymore - triggered by load in the guest. - it seems it is easier to trigger with -smp 2 - host shows qemu process with 100% cpu - seems to be cured by --no-kvm-irqchip - --no-kvm-pit does not help - qmeu console command system_reset works Right now, guest OS is linux 2.6.27.1 Latest KVM from git, host is 2.6.28. Older kvms seem to exhibit the same problem. short gdb session: Program received signal SIGINT, Interrupt. [Switching to Thread 0x7f9dfbb7c6f0 (LWP 13898)] 0x00007f9dfa4e1a92 in select () from /lib/libc.so.6 (gdb) info threads 2 Thread 0x7f9dd7d54950 (LWP 13907) 0x00007f9dfa4e1027 in ioctl () from /lib/libc.so.6 * 1 Thread 0x7f9dfbb7c6f0 (LWP 13898) 0x00007f9dfa4e1a92 in select () from /lib/libc.so.6 (gdb) bt #0 0x00007f9dfa4e1a92 in select () from /lib/libc.so.6 #1 0x0000000000409a2b in main_loop_wait (timeout=0) at /usr/src/kvm-userspace/qemu/vl.c:3639 #2 0x0000000000518c6a in kvm_main_loop () at /usr/src/kvm-userspace/qemu/qemu-kvm.c:600 #3 0x000000000040db93 in main (argc=, argv=0x7fff03badc08, envp=) at /usr/src/kvm-userspace/qemu/vl.c:3801 (gdb) thread 2 [Switching to thread 2 (Thread 0x7f9dd7d54950 (LWP 13907))]#0 0x00007f9dfa4e1027 in ioctl () from /lib/libc.so.6 (gdb) bt #0 0x00007f9dfa4e1027 in ioctl () from /lib/libc.so.6 #1 0x0000000000545d8e in kvm_run (kvm=0xde1040, vcpu=0, env=0xe5b070) at libkvm.c:887 #2 0x0000000000518d89 in kvm_cpu_exec (env=) at /usr/src/kvm-userspace/qemu/qemu-kvm.c:210 #3 0x0000000000519078 in ap_main_loop (_env=) at /usr/src/kvm-userspace/qemu/qemu-kvm.c:417 #4 0x00007f9dfb032007 in start_thread () from /lib/libpthread.so.0 #5 0x00007f9dfa4e838d in clone () from /lib/libc.so.6 #6 0x0000000000000000 in ?? () kvm is started by: /usr/local/bin/qemu-system-x86_64 -vnc :2 -drive file=/dev/mapper/mykvmparition,if=virtio,boot=on -net nic,model=virtio,macaddr=52:54:00:12:34:a0 -net tap,script=/etc/kvm/kvm-ifup,downscript=/etc/kvm/kvm-ifdown -m 512 Host is an AMD 4850e, all OS are 64bit. The syslog on the host seems clean. If you have anything for me to try or need some more information, let me know. Best regards, Jan