Re: KVM host kernel hang

[Alexander Graf <agraf@suse.de>]

Avi Kivity wrote:
> Alexander Graf wrote:
>>
>> I have CONFIG_LOCKDEP_SUPPORT=y. How do I make it detect that it's
>> actually locking itself up?
>> Btw: The issue seems to be easily reproducible :-)
>
> Perhaps CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP.  _SUPPORT just
> indicates the arch can do it if you want, IIUC.

I just added some debug #define's to show me where exactly things break.


Jan  7 14:34:46 linux-dp8n kernel: 2149: Grabbing lock {
Jan  7 14:34:46 linux-dp8n kernel: 1908: Grabbing lock {

   2145 mmio:
   2146         /*
   2147          * Is this MMIO handled locally?
   2148          */
   2149         mutex_lock(&vcpu->kvm->lock);
   2150         mmio_dev = vcpu_find_mmio_dev(vcpu, gpa, bytes, 0);
   2151         if (mmio_dev) {
   2152                 kvm_iodevice_read(mmio_dev, gpa, bytes, val);
   2153                 mutex_unlock(&vcpu->kvm->lock);
   2154                 return X86EMUL_CONTINUE;
   2155         }
   2156         mutex_unlock(&vcpu->kvm->lock);

   1901         case KVM_IRQ_LINE: {
   1902                 struct kvm_irq_level irq_event;
   1903
   1904                 r = -EFAULT;
   1905                 if (copy_from_user(&irq_event, argp, sizeof
irq_event))
   1906                         goto out;
   1907                 if (irqchip_in_kernel(kvm)) {
   1908                         mutex_lock(&kvm->lock);
   1909                         kvm_set_irq(kvm,
KVM_USERSPACE_IRQ_SOURCE_ID,
   1910                                     irq_event.irq, irq_event.level);
   1911                         mutex_unlock(&kvm->lock);
   1912                         r = 0;
   1913                 }
   1914                 break;
   1915         }

Any ideas?

Alex