commit 3f16a5c3 upstream.

This warning can be triggered easily by userspace, so it should certainly not
cause a panic if panic_on_warn is set.

Reported-by: syzbot+c03f30b4f4c46bdf8575@syzkaller.appspotmail.com
Suggested-by: NAlexander Potapenko <glider@google.com>
Acked-by: NAlexander Potapenko <glider@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>