KVM: fix the race while wakeup all pv guest (64f638c7) · Commits · 戴 / test

In kvm_async_pf_wakeup_all(), we add a dummy apf to vcpu->async_pf.done without holding vcpu->async_pf.lock, it will break if we are handling apfs at this time. Also use 'list_empty_careful()' instead of 'list_empty()' Signed-off-by:

Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Acked-by:

Gleb Natapov <gleb@redhat.com> Signed-off-by:

Marcelo Tosatti <mtosatti@redhat.com>

virt/kvm/async_pf.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -196,7 +196,7 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
		{
		struct kvm_async_pf *work;

		if (!list_empty(&vcpu->async_pf.done))
		if (!list_empty_careful(&vcpu->async_pf.done))
		return 0;

		work = kmem_cache_zalloc(async_pf_cache, GFP_ATOMIC);
		@@ -207,7 +207,10 @@ int kvm_async_pf_wakeup_all(struct kvm_vcpu *vcpu)
		get_page(bad_page);
		INIT_LIST_HEAD(&work->queue); /* for list_del to work */

		spin_lock(&vcpu->async_pf.lock);
		list_add_tail(&work->link, &vcpu->async_pf.done);
		spin_unlock(&vcpu->async_pf.lock);

		vcpu->async_pf.queued++;
		return 0;
		}

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