mm: fix invalid node in alloc_migrate_target()

It is incorrect to use next_node to find a target node, it will return
MAX_NUMNODES or invalid node.  This will lead to crash in buddy system
allocation.

Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Laura Abbott" <lauraa@codeaurora.org>
Cc: Hui Zhu <zhuhui@xiaomi.com>
Cc: Wang Xiaoqiang <wangxq10@lzu.edu.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 92c4c36501e7c55dc50b9ae330299c978c329d0a..31555b689eb9b2f1812a10bde083c4951baa86e0 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -289,11 +289,11 @@ struct page *alloc_migrate_target(struct page *page, unsigned long private,
         * now as a simple work-around, we use the next node for destination.
         */
        if (PageHuge(page)) {
-               nodemask_t src = nodemask_of_node(page_to_nid(page));
-               nodemask_t dst;
-               nodes_complement(dst, src);
+               int node = next_online_node(page_to_nid(page));
+               if (node == MAX_NUMNODES)
+                       node = first_online_node;
                return alloc_huge_page_node(page_hstate(compound_head(page)),
-                                           next_node(page_to_nid(page), dst));
+                                           node);
        }
 
        if (PageHighMem(page))