From: Muchun Song songmuchun@bytedance.com
mainline inclusion from mainline-v5.11-rc1 commit 2484be0f88dc6c9670362d51f6a04f2da0626b50 category: bugfix bugzilla: NA CVE: NA
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A max order page has no buddy page and never merges to another order. So isolating and then freeing it is pointless.
Link: https://lkml.kernel.org/r/20201202122114.75316-1-songmuchun@bytedance.com Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock") Signed-off-by: Muchun Song songmuchun@bytedance.com Reviewed-by: Andrew Morton akpm@linux-foundation.org Acked-by: Vlastimil Babka vbabka@suse.cz Reviewed-by: David Hildenbrand david@redhat.com Reviewed-by: Oscar Salvador osalvador@suse.de Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Matthew Wilcox willy@infradead.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org
conflict: mm/page_isolation.c
Signed-off-by: Tong Tiangen tongtiangen@huawei.com Reviewed-by: Chen Wandun chenwandun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/page_isolation.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 019280712e1b8..cdc33cd2203d1 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -111,7 +111,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) */ if (PageBuddy(page)) { order = page_order(page); - if (order >= pageblock_order) { + if (order >= pageblock_order && order < MAX_ORDER - 1) { pfn = page_to_pfn(page); buddy_pfn = __find_buddy_pfn(pfn, order); buddy = page + (buddy_pfn - pfn);