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Date: Sun, 07 Oct 2012 17:22:35 +0800
From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
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To: Jiri Slaby <jslaby@suse.cz>
CC: Avi Kivity <avi@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
        kvm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        Jiri Slaby <jirislaby@gmail.com>
Subject: Re: KVM: WARNING: at .. kvm_release_pfn_clean
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On 10/05/2012 04:33 PM, Jiri Slaby wrote:
> Hi,
> 
> I'm getting this warning while running qemu-kvm 1.2.rc1 on the top of
> 3.6.0-next-20121001:
> WARNING: at virt/kvm/kvm_main.c:1325 kvm_release_pfn_clean+0x70/0x80()
> Hardware name: To Be Filled By O.E.M.
> Modules linked in: nls_cp437 vfat fat dvb_usb_dib0700 dib0090 dib7000p
> dib7000m dib0070 dib8000 dib3000mc dibx000_common microcode
> Pid: 11848, comm: qemu-kvm Tainted: G        W
> 3.6.0-next-20121001_64+ #70
> Call Trace:
>  [<ffffffff8107f19f>] warn_slowpath_common+0x7f/0xc0
>  [<ffffffff8107f1fa>] warn_slowpath_null+0x1a/0x20
>  [<ffffffff81004cd0>] kvm_release_pfn_clean+0x70/0x80
>  [<ffffffff81027ac6>] paging64_page_fault+0x686/0x830
>  [<ffffffff81024745>] ? paging64_gva_to_gpa+0x35/0x80
>  [<ffffffff81021121>] kvm_mmu_page_fault+0x31/0x100
>  [<ffffffff81040e81>] handle_exception+0x231/0x3d0
>  [<ffffffff81041fbc>] vmx_handle_exit+0xcc/0x780
>  [<ffffffff8101be44>] kvm_arch_vcpu_ioctl_run+0x444/0xf60
>  [<ffffffff81017117>] ? kvm_arch_vcpu_load+0x57/0x1b0
>  [<ffffffff81005302>] kvm_vcpu_ioctl+0x472/0x610
>  [<ffffffff811aa36b>] ? fsnotify+0x24b/0x340
>  [<ffffffff8117d609>] do_vfs_ioctl+0x99/0x580
>  [<ffffffff810b620b>] ? pick_next_task_fair+0x13b/0x1a0
>  [<ffffffff810b4f68>] ? __enqueue_entity+0x78/0x80
>  [<ffffffff81010114>] ? kvm_on_user_return+0x64/0x70
>  [<ffffffff8117db40>] sys_ioctl+0x50/0x90
>  [<ffffffff816a46e2>] system_call_fastpath+0x16/0x1b
> 
> I.e. is_error_pfn(pfn) is true.

Jiri, thanks for your report!

This is a known bug which can be fixed by this patch:
	https://lkml.org/lkml/2012/9/21/46

But this patch need be improved, i will post the new version after
full test.