[COMMIT master] KVM: fix the race while wakeup all pv guest

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxx>
Acked-by: Gleb Natapov <gleb@xxxxxxxxxx>
Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx>

diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c
index 100c66e..74268b4 100644
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -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;
 }
--
To unsubscribe from this list: send the line "unsubscribe kvm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [KVM Development]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Walks]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux