Commit ef70b6f4 authored Jul 14, 2016 by Mel Gorman Committed by Linus Torvalds Jul 15, 2016

mm, meminit: ensure node is online before checking whether pages are uninitialised

early_page_uninitialised looks up an arbitrary PFN. While a machine
without node 0 will boot with "mm, page_alloc: Always return a valid
node from early_pfn_to_nid", it works because it assumes that nodes are
always in PFN order. This is not guaranteed so this patch adds
robustness by always checking if the node being checked is online.

Link: http://lkml.kernel.org/r/1468008031-3848-4-git-send-email-mgorman@techsingularity.net

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e4568d38

mm/page_alloc.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -286,7 +286,9 @@ static inline void reset_deferred_meminit(pg_data_t *pgdat)
		/* Returns true if the struct page for the pfn is uninitialised */
		static inline bool __meminit early_page_uninitialised(unsigned long pfn)
		{
		if (pfn >= NODE_DATA(early_pfn_to_nid(pfn))->first_deferred_pfn)
		int nid = early_pfn_to_nid(pfn);

		if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
		return true;

		return false;