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Date: Tue, 28 Oct 2014 10:02:32 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
 "kvm-ppc@vger.kernel.org" <kvm-ppc@vger.kernel.org>,
 Paul Mackerras <paulus@samba.org>,
 linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: lockdep warning with 2d65a9f48fcdf7866aab6457bc707ca233e0c791
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On 10/15/2014 07:28 PM, Aneesh Kumar K.V wrote:
> 
> =============================================
> [ INFO: possible recursive locking detected ]
> 3.17.0+ #31 Not tainted
> ---------------------------------------------
> qemu-system-ppc/9112 is trying to acquire lock:
>  (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [<d000000011591f84>] .vcore_stolen_time+0x44/0xb0 [kvm_hv]
> 
> but task is already holding lock:
>  (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [<d000000011592524>] .kvmppc_remove_runnable.part.2+0x34/0xd0 [kvm_hv]

This must come from here:

        while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&
               (vc->vcore_state == VCORE_RUNNING ||
                vc->vcore_state == VCORE_EXITING)) {
                spin_unlock(&vc->lock);
                kvmppc_wait_for_exec(vcpu, TASK_UNINTERRUPTIBLE);
                spin_lock(&vc->lock);
        }

        if (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE) {
                kvmppc_remove_runnable(vc, vcpu);
                vcpu->stat.signal_exits++;
                kvm_run->exit_reason = KVM_EXIT_INTR;
                vcpu->arch.ret = -EINTR;
        }


if vc->vcore_state is VCORE_SLEEPING (I think it cannot be VCORE_STARTING)?

Paolo