Re: [PATCH] kvm: fix waitqueue_active without memory barrier in virt/kvm/async_pf.c

From: Paolo Bonzini
Date: Fri Oct 09 2015 - 06:27:11 EST




On 09/10/2015 11:04, Kosuke Tatsukawa wrote:
> smp_store_mb() called from set_current_state(), which is called from
> prepare_to_wait() should prevent reordering such as below from
> happening. wait_event*() also calls set_current_state() inside.

Ah, I missed that set_current_state has a memory barrier in it. The
patch is okay, but please expand the comment to say that this memory
barrier pairs with prepare_to_wait's set_current_state().

Paolo
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