Re: WARNING: at /usr/src/modules/kvm/mmu.c:390 account_shadowed()

[Avi Kivity <avi@qumranet.com>]

Thomas Cataldo wrote:
> On Mon, Apr 21, 2008 at 9:57 PM, Thomas Cataldo
> <thomas.cataldo@aliasource.fr> wrote:
>   
>> Hi,
>>
>>  I am running kvm-66 on top of a debian sid host with 2.6.24 (intel 32bit host).
>>
>>  Got the following in my logs today :
>>
>>  Apr 21 17:55:01 buffy kernel: WARNING: at
>>  /usr/src/modules/kvm/mmu.c:390 account_shadowed()
>>  Apr 21 17:55:01 buffy kernel: Pid: 21416, comm: kvm Tainted: P
>>  2.6.24-1-686 #1
>>  Apr 21 17:55:01 buffy kernel:  [<f8d07a36>] kvm_mmu_get_page+0x42d/0x447 [kvm]
>>  Apr 21 17:55:01 buffy kernel:  [<f8d08cca>] kvm_mmu_load+0xdf/0x15c [kvm]
>>  Apr 21 17:55:01 buffy kernel:  [<f8affe41>]
>>  vmx_queue_exception+0x0/0x33 [kvm_intel]
>>  Apr 21 17:55:01 buffy kernel:  [<f8d05521>]
>>  kvm_arch_vcpu_ioctl_run+0x233/0x5a9 [kvm]
>>  Apr 21 17:55:01 buffy kernel:  [<f8d013aa>] kvm_vcpu_ioctl+0xe4/0x34c [kvm]
>>  Apr 21 17:55:01 buffy kernel:  [<c0159078>] delayacct_end+0x70/0x77
>>  Apr 21 17:55:01 buffy kernel:  [<c015aa19>] sync_page+0x0/0x3b
>>  Apr 21 17:55:01 buffy kernel:  [<c0159388>] __delayacct_blkio_end+0x5b/0x5f
>>  Apr 21 17:55:01 buffy kernel:  [<c02bcaab>] io_schedule+0x64/0x80
>>  Apr 21 17:55:01 buffy kernel:  [<c011e07d>] enqueue_entity+0x2b/0x3d
>>  Apr 21 17:55:01 buffy kernel:  [<c0115343>] apic_wait_icr_idle+0xe/0x15
>>  Apr 21 17:55:01 buffy kernel:  [<c011e0a5>] enqueue_task_fair+0x16/0x24
>>  Apr 21 17:55:01 buffy kernel:  [<c011d643>] enqueue_task+0x52/0x5d
>>  Apr 21 17:55:01 buffy kernel:  [<c011de9e>] resched_task+0x52/0x54
>>  Apr 21 17:55:01 buffy kernel:  [<c011f459>] try_to_wake_up+0x2b8/0x2c2
>>  Apr 21 17:55:01 buffy kernel:  [<c011d47e>] __wake_up_common+0x32/0x5c
>>  Apr 21 17:55:01 buffy kernel:  [<c011eecc>] __wake_up+0x32/0x42
>>  Apr 21 17:55:01 buffy kernel:  [<c013e25c>] wake_futex+0x3b/0x45
>>  Apr 21 17:55:01 buffy kernel:  [<c013e4de>] futex_wake+0x81/0xb0
>>  Apr 21 17:55:01 buffy kernel:  [<c013f097>] do_futex+0x77/0x983
>>  Apr 21 17:55:01 buffy kernel:  [<c011d9ca>] update_curr+0x62/0xef
>>  Apr 21 17:55:01 buffy kernel:  [<c0103044>] __switch_to+0x9d/0x11d
>>  Apr 21 17:55:01 buffy kernel:  [<f8d012c6>] kvm_vcpu_ioctl+0x0/0x34c [kvm]
>>  Apr 21 17:55:01 buffy kernel:  [<c018285b>] do_ioctl+0x1f/0x62
>>  Apr 21 17:55:01 buffy kernel:  [<c0182ad5>] vfs_ioctl+0x237/0x249
>>  Apr 21 17:55:01 buffy kernel:  [<c0182b2c>] sys_ioctl+0x45/0x5d
>>  Apr 21 17:55:01 buffy kernel:  [<c0103e5e>] sysenter_past_esp+0x6b/0xa1
>>
>>
>>  Regards,
>>  Thomas.
>>
>>     
>
> as I got no reply, I guess it is a bad setup on my part. If that might
> help, this happenned while I was doing a "make -j" on webkit svn tree
> (ie. heavy c++ compilation workload) .
>
>   

No this is not bad setup.  No amount of bad setup should give this warning.

You didn't get a reply because no one knows what to make of it, and 
because it's much more fun to debate endianess or contemplete guests 
with eighty thousand disks than to fix those impossible bugs.  If you 
can give clear instructions on how to reproduce this, we will try it 
out.  Please be sure to state OS name and versions for the guest as well 
as the host.

-- 
Any sufficiently difficult bug is indistinguishable from a feature.


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