2017-06-07 21:05 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>: > > > On 07/06/2017 14:04, Wanpeng Li wrote: >> From: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> >> >> 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
