From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric B Munson Subject: Re: WARNING: at arch/x86/kernel/kvmclock.c:127 Date: Wed, 06 Jun 2012 11:52:23 -0400 Message-ID: <85da505e126816fdbef06accbb17ff98@mgebm.net> References: <1338920459.20088.41.camel@mendozza.osrc.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: , , , , , Joerg Roedel , To: Frank Arnold Return-path: Received: from oz.csail.mit.edu ([128.30.30.239]:37996 "EHLO mail.mgebm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026Ab2FFQNn (ORCPT ); Wed, 6 Jun 2012 12:13:43 -0400 In-Reply-To: <1338920459.20088.41.camel@mendozza.osrc.amd.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, 5 Jun 2012 20:20:59 +0200, Frank Arnold wrote: > 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. > This warning kicks off if the watchdog_timer_fn function is called outside of an atomic context, the warning itself is not re > ------------[ 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