Commit 92fb1db2 authored Jun 07, 2020 by SeongJae Park Committed by Linus Torvalds Jun 08, 2020

mm/page_idle.c: skip offline pages



'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>

parent 9aa900c8

mm/page_idle.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -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);
		pg_data_t *pgdat;

		if (!pfn_valid(pfn))
		return NULL;

		page = pfn_to_page(pfn);
		if (!page \|\| !PageLRU(page) \|\|
		!get_page_unless_zero(page))
		return NULL;

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