Commit 6f25a14a authored Apr 01, 2016 by Xishi Qiu Committed by Linus Torvalds Apr 01, 2016

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: c8721bbb ("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>

parent 969e8d7e

mm/page_isolation.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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))

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