Re: [PATCH] kvm: async_pf: fix rcu_irq_enter() with irqs enabled

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

On Wed, Apr 26, 2017 at 04:56:26PM +0200, Paolo Bonzini wrote:
> native_safe_halt enables interrupts, and you just shouldn't
> call rcu_irq_enter() with interrupts enabled.  Reorder the
> call with the following local_irq_disable() to respect the
> invariant.
> 
> Reported-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

> ---
>  arch/x86/kernel/kvm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 14f65a5f938e..2a7835932b71 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -161,8 +161,8 @@ void kvm_async_pf_task_wait(u32 token)
>  			 */
>  			rcu_irq_exit();
>  			native_safe_halt();
> -			rcu_irq_enter();
>  			local_irq_disable();
> +			rcu_irq_enter();
>  		}
>  	}
>  	if (!n.halted)
> -- 
> 2.9.3
>