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Re: [PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage

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2017-06-07 21:05 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>
>
> On 07/06/2017 14:04, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> Commit 9b132fbe5419 (Add rcu user eqs exception hooks for async page fault)
>> adds rcu_irq_enter/exit() to kvm_async_pf_task_wait() to exit cpu idle eqs
>> when needed, to protect the code that needs use rcu. There is no need to call
>> this pairs if async page fault is not triggered from idle task.
>>
>> This patch fixes it by rcu irq exit if it is not triggered from idle task to
>> avoid rcu hang after schedule() in the for loop.
>
> How does the bug manifest?

Just by codes review.

Regards,
Wanpeng Li

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[PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage Wanpeng Li <kernellwp@gmail.com> - 2017-06-07 14:10 +0200
  Re: [PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage Paolo Bonzini <pbonzini@redhat.com> - 2017-06-07 15:10 +0200
    Re: [PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage Wanpeng Li <kernellwp@gmail.com> - 2017-06-07 16:20 +0200
      Re: [PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage Paolo Bonzini <pbonzini@redhat.com> - 2017-06-07 16:30 +0200
        Re: [PATCH] KVM: async_pf: Fix rcu_irq_enter/exit() usage Wanpeng Li <kernellwp@gmail.com> - 2017-06-08 10:10 +0200

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