[Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[changlimin]

[-- Attachment #1: Type: text/plain, Size: 95 bytes --]

BTW windows 2008 guest start failed at qem-kvm 0.13.0, but 0.12.5 start success.

Best regards

[-- Attachment #2: Type: text/html, Size: 453 bytes --]

Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[Mulyadi Santosa]

2010/12/15 changlimin <changlimin@h3c.com>:
> BTW windows 2008 guest start failed at qem-kvm 0.13.0, but 0.12.5 start
> success.

I am not qemu/kvm expert, but I think if you could provide either qemu
instruction trace (using -d) or traces inside the guest OS itself
(windows live debugger maybe?), it would  be much easier for people
here to decipher the problem.

At least could you write down how do you invoke qemu-kvm back then?

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[changlimin]

1. I create a guest use libvirt;
2. I start the guest use: virsh start guest;
3. I save the guest to a file, use: virsh save guest guest.save
4. I retore the guest, use : virsh retore guest.save
    Sometimes, the guest restore successful. sometimes restore fail. 
    I debug the code, the qemu-kvm hang at  kvm_put_vcpu_events, the process state is D, uninterruptable sleep. Only can killed by kill -9.
    I print the events when kvm_put_vcpu_events / kvm_get_vcpu_events, it is always different, event when restore successful

----- Original Message ----- 
From: "Mulyadi Santosa" <mulyadi.santosa@gmail.com>
To: "changlimin" <changlimin@h3c.com>
Cc: <qemu-devel@nongnu.org>
Sent: Wednesday, December 15, 2010 3:46 PM
Subject: Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0


> 2010/12/15 changlimin <changlimin@h3c.com>:
>> BTW windows 2008 guest start failed at qem-kvm 0.13.0, but 0.12.5 start
>> success.
> 
> I am not qemu/kvm expert, but I think if you could provide either qemu
> instruction trace (using -d) or traces inside the guest OS itself
> (windows live debugger maybe?), it would  be much easier for people
> here to decipher the problem.
> 
> At least could you write down how do you invoke qemu-kvm back then?
> 
> -- 
> regards,
> 
> Mulyadi Santosa
> Freelance Linux trainer and consultant
> 
> blog: the-hydra.blogspot.com
> training: mulyaditraining.blogspot.com
>

Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[Mulyadi Santosa]

On Wed, Dec 15, 2010 at 15:08, changlimin <changlimin@h3c.com> wrote:
> 1. I create a guest use libvirt;
> 2. I start the guest use: virsh start guest;
> 3. I save the guest to a file, use: virsh save guest guest.save
> 4. I retore the guest, use : virsh retore guest.save
>    Sometimes, the guest restore successful. sometimes restore fail.
>    I debug the code, the qemu-kvm hang at  kvm_put_vcpu_events, the process state is D, uninterruptable sleep. Only can killed by kill -9.
>    I print the events when kvm_put_vcpu_events / kvm_get_vcpu_events, it is always different, event when restore successful

I could only say, i smell deadlock due to race condition here...but I
have no further prove...how many (virtual) CPU did you simulate at
that time?

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0

[changlimin]

I have tried 1 vcpu and 2 vcpus, both sometimes restore fail.



----- Original Message ----- 
From: "Mulyadi Santosa" <mulyadi.santosa@gmail.com>
To: "changlimin" <changlimin@h3c.com>
Cc: <qemu-devel@nongnu.org>
Sent: Wednesday, December 15, 2010 4:31 PM
Subject: Re: [Qemu-devel] Sometimes qem-kvm hang at kvm_put_vcpu_events when virsh restore. Both version 0.12.5 / 0.13.0


On Wed, Dec 15, 2010 at 15:08, changlimin <changlimin@h3c.com> wrote:
> 1. I create a guest use libvirt;
> 2. I start the guest use: virsh start guest;
> 3. I save the guest to a file, use: virsh save guest guest.save
> 4. I retore the guest, use : virsh retore guest.save
> Sometimes, the guest restore successful. sometimes restore fail.
> I debug the code, the qemu-kvm hang at kvm_put_vcpu_events, the process state is D, uninterruptable sleep. Only can killed by kill -9.
> I print the events when kvm_put_vcpu_events / kvm_get_vcpu_events, it is always different, event when restore successful

I could only say, i smell deadlock due to race condition here...but I
have no further prove...how many (virtual) CPU did you simulate at
that time?

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com