Re: [PATCH] Fix QEMU vcpu thread race with apic_reset

[Ulrich Drepper <drepper@redhat.com>]

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> @@ -369,6 +372,10 @@ static void *ap_main_loop(void *_env)
>      sigfillset(&signals);
>      sigprocmask(SIG_BLOCK, &signals, NULL);
>      kvm_create_vcpu(kvm_context, env->cpu_index);
> +    pthread_mutex_lock(&vcpu_mutex);
> +    vcpu->created = 1;
> +    pthread_cond_signal(&qemu_vcpuup_cond);
> +    pthread_mutex_unlock(&vcpu_mutex);
>      kvm_qemu_init_env(env);
>      kvm_main_loop_cpu(env);
>      return NULL;

Still no locking needed on any CPU we support.  The memory access is
atomic and that's all that counts here.  With the mutex taken the woken
thread immediately runs into a brick wall and has to be put to sleep again.

- --
➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖
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