From: SeongJae Park sjpark@amazon.de
mainline inclusion from mainline-v5.8-rc1 commit 92fb1db26eefc11554820f11ce8e92007da2fbf4 category: bugfix bugzilla: 37584 CVE: NA
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'Idle page tracking' users can pass random pfn that might be mapped to an offline page. To avoid accessing such pages, this commit modifies the 'page_idle_get_page()' to use 'pfn_to_online_page()' instead of 'pfn_valid()' and 'pfn_to_page()' combination, so that the pfn mapped to an offline page can be skipped.
Reported-by: David Hildenbrand david@redhat.com Signed-off-by: SeongJae Park sjpark@amazon.de Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: David Hildenbrand david@redhat.com Reviewed-by: Pankaj Gupta pankaj.gupta.linux@gmail.com Link: http://lkml.kernel.org/r/20200605092502.18018-2-sjpark@amazon.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/page_idle.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/mm/page_idle.c b/mm/page_idle.c index 52ed59bbc275..7881bc643bbb 100644 --- a/mm/page_idle.c +++ b/mm/page_idle.c @@ -4,6 +4,7 @@ #include <linux/fs.h> #include <linux/sysfs.h> #include <linux/kobject.h> +#include <linux/memory_hotplug.h> #include <linux/mm.h> #include <linux/mmzone.h> #include <linux/pagemap.h> @@ -30,13 +31,9 @@ */ static struct page *page_idle_get_page(unsigned long pfn) { - struct page *page; + struct page *page = pfn_to_online_page(pfn); struct zone *zone;
- if (!pfn_valid(pfn)) - return NULL; - - page = pfn_to_page(pfn); if (!page || !PageLRU(page) || !get_page_unless_zero(page)) return NULL;