From: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxxx Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [4.2+] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff -puN mm/page_alloc.c~mm-meminit-ensure-node-is-online-before-checking-whether-pages-are-uninitialised mm/page_alloc.c --- a/mm/page_alloc.c~mm-meminit-ensure-node-is-online-before-checking-whether-pages-are-uninitialised +++ a/mm/page_alloc.c @@ -286,7 +286,9 @@ static inline void reset_deferred_memini /* 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
