hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

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Check whether page is NULL or not in page_reliable(). Return false if page
is NULL.
Signed-off-by: NMa Wupeng <mawupeng1@huawei.com>
Reviewed-by: Kefeng Wang<wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>