proposing 7df003c85218b5f for v5.5.y, v5.4.y, 4.19.y, v4.14.y, v4.9.y

Hello,

the following one line commit

commit 7df003c85218b5f5b10a7f6418208f31e813f38f Author: Zhuang Yanying ann.zhuangyanying@huawei.com Date: Sat Oct 12 11:37:31 2019 +0800

KVM: fix overflow of zero page refcount with ksm running

applies cleanly to v5.5.y, v5.4.y, 4.19.y, v4.14.y and v4.9.y.

I actually ran into that bug on 4.9.y

Thanks in advance,

Thomas