From: Muchun Song <songmuchun@bytedance.com> mainline inclusion from mainline-v5.11-rc1 commit 2484be0f88dc6c9670362d51f6a04f2da0626b50 category: bugfix bugzilla: NA CVE: NA ----------------------------------------------- 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); -- 2.25.1