Commit b3618455 authored by Miaohe Lin's avatar Miaohe Lin Committed by Andrew Morton
Browse files

mm/page_alloc: add missing is_migrate_isolate() check in set_page_guard() 

In MIGRATE_ISOLATE case, zone freepage state shouldn't be modified as
caller will take care of it.  Add missing is_migrate_isolate() here to
avoid possible unbalanced freepage state.  This would happen if someone
isolates the block, and then we face an MCE failure/soft-offline on a page
within that block.  __mod_zone_freepage_state() will be triggered via
below call trace which already had been triggered back when block was
isolated:

take_page_off_buddy
  break_down_buddy_pages
    set_page_guard

Link: https://lkml.kernel.org/r/20220916072257.9639-9-linmiaohe@huawei.com


Fixes: 06be6ff3 ("mm,hwpoison: rework soft offline for free pages")
Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 30e3b5d7

mm/page_alloc.c

+2 −1
Original line number Diff line number Diff line
@@ -873,6 +873,7 @@ static inline bool set_page_guard(struct zone *zone, struct page *page, 
	INIT_LIST_HEAD(&page->buddy_list);

	set_page_private(page, order);

	/* Guard pages are not available for any usage */

	if (!is_migrate_isolate(migratetype))

		__mod_zone_freepage_state(zone, -(1 << order), migratetype);



	return true;