From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Arnold Subject: WARNING: at arch/x86/kernel/kvmclock.c:127 Date: Tue, 5 Jun 2012 20:20:59 +0200 Message-ID: <1338920459.20088.41.camel@mendozza.osrc.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: , , , , , Joerg Roedel , To: Return-path: Received: from ch1ehsobe003.messaging.microsoft.com ([216.32.181.183]:50313 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755980Ab2FESVK (ORCPT ); Tue, 5 Jun 2012 14:21:10 -0400 Sender: kvm-owner@vger.kernel.org List-ID: Hi all, I observed the following warning during testing of 3.5-rc1, involving some intensive and random CPU online state toggling through sysfs. It only shows up about 1 out of 500 times. Also, there was no KVM guest running on the system. ------------[ cut here ]------------ WARNING: at arch/x86/kernel/kvmclock.c:127 kvm_check_and_clear_guest_paused+0x52/0x60() Hardware name: Dinar Modules linked in: nfs lockd fscache auth_rpcgss nfs_acl sunrpc ipv6 ext4 jbd2 dm_mod powernow_k8 freq_table mperf kvm_amd kvm crc32c_intel ghash_clmulni_intel aesni_intel cryptd aes_x86_64 aes_generic microcode serio_raw pcspkr k10temp amd64_edac_mod edac_core edac_mce_amd i2c_piix4 sg bnx2 ext3 jbd mbcache sr_mod cdrom sd_mod crc_t10dif ata_generic pata_acpi pata_atiixp ahci libahci usb_storage radeon ttm drm_kms_helper drm i2c_algo_bit i2c_core [last unloaded: scsi_wait_scan] Pid: 3593, comm: py_topology Not tainted 3.5.0-rc1+ #1 Call Trace: [] warn_slowpath_common+0x7f/0xc0 [] warn_slowpath_null+0x1a/0x20 [] kvm_check_and_clear_guest_paused+0x52/0x60 [] watchdog_timer_fn+0x97/0x1b0 [] __run_hrtimer+0x83/0x1d0 [] ? touch_softlockup_watchdog_sync+0x40/0x40 [] hrtimer_interrupt+0x106/0x240 [] migrate_hrtimers+0x138/0x1a0 [] hrtimer_cpu_notify+0xe4/0xeb [] notifier_call_chain+0x55/0x80 [] __raw_notifier_call_chain+0xe/0x10 [] __cpu_notify+0x20/0x40 [] cpu_notify_nofail+0x15/0x30 [] _cpu_down+0x12d/0x270 [] cpu_down+0x36/0x50 [] store_online+0x74/0xd0 [] dev_attr_store+0x20/0x30 [] sysfs_write_file+0xef/0x170 [] vfs_write+0xc8/0x190 [] sys_write+0x51/0x90 [] system_call_fastpath+0x16/0x1b ---[ end trace 574db9e069f4f35e ]--- This is a regression introduced by the following commit: commit 3b5d56b9317fa7b5407dff1aa7b115bf6cdbd494 Author: Eric B Munson Date: Sat Mar 10 14:37:26 2012 -0500 kvmclock: Add functions to check if the host has stopped the vm When a host stops or suspends a VM it will set a flag to show this. The watchdog will use these functions to determine if a softlockup is real, or the result of a suspended VM. Signed-off-by: Eric B Munson asm-generic changes Acked-by: Arnd Bergmann Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity -- Regards, Frank Arnold Advanced Micro Devices GmbH Einsteinring 24, 85609 Dornach GM: Alberto Bozzo Reg: Dornach, Landkreis Muenchen HRB Nr. 43632 WEEE Registernr: 129 19551