memory-hotplug: bug fix race between isolation and allocation
memory-hotplug: bug fix race between isolation and allocation

Like below, memory-hotplug makes race between page-isolation
and page-allocation so it can hit BUG_ON in __offline_isolated_pages.

	CPU A					CPU B

start_isolate_page_range
set_migratetype_isolate
spin_lock_irqsave(zone->lock)

				free_hot_cold_page(Page A)
				/* without zone->lock */
				migratetype = get_pageblock_migratetype(Page A);
				/*
				 * Page could be moved into MIGRATE_MOVABLE
				 * of per_cpu_pages
				 */
				list_add_tail(&page->lru, &pcp->lists[migratetype]);

set_pageblock_isolate
move_freepages_block
drain_all_pages

				/* Page A could be in MIGRATE_MOVABLE of free_list. */

check_pages_isolated
__test_page_isolated_in_pageblock
/*
 * We can't catch freed page which
 * is free_list[MIGRATE_MOVABLE]
 */
if (PageBuddy(page A))
	pfn += 1 << page_order(page A);

				/* So, Page A could be allocated */

__offline_isolated_pages
/*
 * BUG_ON hit or offline page
 * which is used by someone
 */
BUG_ON(!PageBuddy(page A));

This patch checks page's migratetype in freelist in
__test_page_isolated_in_pageblock.  So now
__test_page_isolated_in_pageblock can check the page caused by above race
and can fail of memory offlining.

Signed-off-by: Minchan Kim <eee62f459f15dcddf87a8df69e8328e2a2562028@kernel.org>
Acked-by: KAMEZAWA Hiroyuki <634f508bd7c47cf0ee4126243675c3e598920fbc@jp.fujitsu.com>
Reviewed-by: Yasuaki Ishimatsu <9b26f769475fafc2d25107053b1bdd774d49438a@jp.fujitsu.com>
Acked-by: Mel Gorman <39ea6a09710987173e32e37c86918024a0f441c1@suse.de>
Cc: Xishi Qiu <dd58e6c73de42ea3812c4e45cc983f071455d7f2@huawei.com>
Cc: Wen Congyang <59c7438a9275f5dd0b96a91958b493a9d005ad46@cn.fujitsu.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs