On Tue, May 07, 2013 at 01:07:06PM +0200, Cornelia Huck wrote:
> On Tue, 7 May 2013 11:21:09 +0200
> Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote:
>
> > On Tue, 7 May 2013 12:12:09 +0300
> > Gleb Natapov <gleb@xxxxxxxxxx> wrote:
> >
> > > On Tue, May 07, 2013 at 05:10:41PM +0800, Asias He wrote:
> > > > On Tue, May 07, 2013 at 11:42:07AM +0300, Gleb Natapov wrote:
> > > > > On Tue, May 07, 2013 at 04:36:50PM +0800, Asias He wrote:
> > > > > > On Tue, May 07, 2013 at 11:18:38AM +0300, Gleb Natapov wrote:
> > > > > > > On Tue, May 07, 2013 at 04:14:50PM +0800, Asias He wrote:
> > > > > > > > On Tue, May 07, 2013 at 10:55:36AM +0300, Gleb Natapov wrote:
> > > > > > > > > On Tue, May 07, 2013 at 09:37:30AM +0800, Asias He wrote:
> > > > > > > > > > Hi,
> > > > > > > > > >
> > > > > > > > > > I am seeing this with linus/master. Any ideas?
> > > > > > > > > >
> > > > > > > > > How reproducible it this? What HEAD are you seeing this with?
> > > > > > > >
> > > > > > > > Almost always. Start a guest with vhost-net on.
> > > > > > > >
> > > > > > > It happens during start or on VM exit? The trace shows do_exit()
> > > > > > >
> > > > > > > > QEMU : e3351000cd682200835763caca87adf708ed1c65
> > > > > > > > KERNEL: 51a26ae7a14b85c99c9be470c2d28eeeba0f26a3
> > > > > > > >
> > > > > > > Can you try with kvm.git next branch?
> > > > > >
> > > > > > With next branch db6ae6158186a17165ef990bda2895ae7594b039,
> > > > > >
> > > > > Can you revert a0f155e9646d5f1c263f6f9aae880151100243bb and try again?
> > > >
> > > > The issue is gone with a0f155e9646d5f1c263f6f9aae880151100243bb
> > > > reverted.
> > > >
> > > Cornelia, any ideas?
> >
> > irqfd_deactivate before kvm_init or after kvm_exit? Let me look...
> >
>
> Hm, no idea.
>
For am quick look is seems that after the patch irqfd_cleanup_wq is
initialized as part of kvm-intel/kvm-amd module, but before the patch is
was initialized as part of kvm module. The later is how it should be,
but I do not see why would it cause the problem.
> Asias, could you try whether the patch below yields any interesting
> backtraces?
>
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 64ee720..59c3810 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -92,6 +92,8 @@ struct _irqfd {
> };
>
> static struct workqueue_struct *irqfd_cleanup_wq;
> +static int irqfd_ready;
> +static unsigned long irqfd_cnt;
>
> static void
> irqfd_inject(struct work_struct *work)
> @@ -410,6 +412,8 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
> */
> fput(file);
>
> + irqfd_cnt++;
> +
> return 0;
>
> fail:
> @@ -483,12 +487,16 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
> */
> flush_workqueue(irqfd_cleanup_wq);
>
> + irqfd_cnt--;
> +
> return 0;
> }
>
> int
> kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
> {
> + WARN_ON(!irqfd_ready);
> +
> if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
> return -EINVAL;
>
> @@ -548,15 +556,22 @@ void kvm_irq_routing_update(struct kvm *kvm,
> */
> int kvm_irqfd_init(void)
> {
> + WARN_ON(irqfd_cnt);
> +
> irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
> if (!irqfd_cleanup_wq)
> return -ENOMEM;
>
> + irqfd_ready = 1;
> +
> return 0;
> }
>
> void kvm_irqfd_exit(void)
> {
> + WARN_ON(irqfd_cnt);
> + irqfd_ready = 0;
> +
> destroy_workqueue(irqfd_cleanup_wq);
> }
> #endif
--
Gleb.
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