linux-kernel - Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at arch/x86/mm/extable.c:50 ex_handler_rdmsr

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Message-ID: <1e840272-9a0c-1e95-0356-12c031df7458@redhat.com>
Date:	Tue, 21 Jun 2016 12:10:11 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Wanpeng Li <kernellwp@...il.com>, Yu Chen <yu.chen.surf@...il.com>,
	kernel test robot <xiaolong.ye@...el.com>
Cc:	Linux PM list <linux-pm@...r.kernel.org>,
	linux-acpi@...r.kernel.org, Len Brown <len.brown@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	kvm <kvm@...r.kernel.org>, Radim Krcmar <rkrcmar@...hat.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Zhang Rui <rui.zhang@...el.com>, lkp@...org
Subject: Re: [LKP] [lkp] [x86 tsc] 19fa5e7364: WARNING: CPU: 0 PID: 0 at
 arch/x86/mm/extable.c:50 ex_handler_rdmsr_unsafe+0x72/0x80



On 21/06/2016 08:08, Wanpeng Li wrote:
> Cc KVM ML, Paolo, Radim,
>>> FYI, raw QEMU command line is:
>>>
>>>         qemu-system-x86_64 -enable-kvm -cpu SandyBridge -kernel /pkg/linux/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/vmlinuz-4.7.0-rc3-00009-g19fa5e7 -append 'root=/dev/ram0 user=lkp job=/lkp/scheduled/vm-kbuild-yocto-x86_64-32/bisect_boot-1-yocto-minimal-x86_64.cgz-x86_64-randconfig-w0-06180628-19fa5e73647fde1e6a7038a8f05cddf4c43f08d3-20160618-25535-h82bax-0.yaml~ ARCH=x86_64 kconfig=x86_64-randconfig-w0-06180628 branch=internal-eywa/master commit=19fa5e73647fde1e6a7038a8f05cddf4c43f08d3 BOOT_IMAGE=/pkg/linux/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/vmlinuz-4.7.0-rc3-00009-g19fa5e7 max_uptime=600 RESULT_ROOT=/result/boot/1/vm-kbuild-yocto-x86_64/yocto-minimal-x86_64.cgz/x86_64-randconfig-w0-06180628/gcc-6/19fa5e73647fde1e6a7038a8f05cddf4c43f08d3/0 LKP_SERVER=inn earlyprintk=ttyS0,115200 systemd.log_level=err debug apic=debug sysrq_always_enabled rcupdate.rcu_cpu_stall_timeout=100 panic=-1 softlockup_panic=1 nmi_watchdog=panic oops=panic load_ramdisk=2 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal rw ip=::::vm-kbuild-yocto-x86_64-32::dhcp drbd.minor_count=8'  -initrd /fs/sdh1/initrd-vm-kbuild-yocto-x86_64-32 -m 320 -smp 1 -device e1000,netdev=net0 -netdev user,id=net0 -boot order=nc -no-reboot -watchdog i6300esb -rtc base=localtime -drive file=/fs/sdh1/disk0-vm-kbuild-yocto-x86_64-32,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-vm-kbuild-yocto-x86_64-32 -serial file:/dev/shm/kboot/serial-vm-kbuild-yocto-x86_64-32 -daemonize -display none -monitor null
>>>
>> This  problem was caused due to kvm does not support MSR_PLATFORM_INFO(0xce),
>> according to Wanpeng's feedback.
>>
>> Hi Wanpeng, is it possible for kvm to simulate this MSR, otherwise we
>> might have to use
>> rdmsr_safe instead.
> 
> There is a thread discussed this before
> https://patchwork.kernel.org/patch/8833021/, MSR_PLATFORM_INFO can't
> be simple emulation.
> 
> Ping Paolo, Radim. :)

rdmsr_safe must be used instead.  I'll prepare a patch.

Paolo