From: Mel Gorman Date: Thu, 14 Jul 2016 19:07:23 +0000 (-0700) Subject: mm, meminit: ensure node is online before checking whether pages are uninitialised X-Git-Tag: Ubuntu-4.10.0-19.21~3019^2~7 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=ef70b6f41cda6270165a6f27b2548ed31cfa3cb2;p=mirror_ubuntu-artful-kernel.git 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 Acked-by: David Rientjes Cc: [4.2+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 5d013526bd0a..8b3e1341b754 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -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;