On 07/06/2017 16:10, Wanpeng Li wrote: > 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. So it's just code cleanup? Paolo
