From c6a3024e2391597a1f4276362614dfdb9102f23a Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 8 Dec 2011 15:41:47 +1100 Subject: [PATCH] mm, debug: test for online nid when allocating on single node Calling alloc_pages_exact_node() means the allocation only passes the zonelist of a single node into the page allocator. If that node isn't online, it's zonelist may never have been initialized causing a strange oops that may not immediately be clear. I recently debugged an issue where node 0 wasn't online and an allocator was passing 0 to alloc_pages_exact_node() and it resulted in a NULL pointer on zonelist->_zoneref. If CONFIG_DEBUG_VM is enabled, though, it would be nice to catch this a bit earlier. Signed-off-by: David Rientjes Acked-by: Mel Gorman Signed-off-by: Andrew Morton --- include/linux/gfp.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/gfp.h b/include/linux/gfp.h index e3b55aced5c3..0f1ce0d13341 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -324,7 +324,7 @@ static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask, static inline struct page *alloc_pages_exact_node(int nid, gfp_t gfp_mask, unsigned int order) { - VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES); + VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES || !node_online(nid)); return __alloc_pages(gfp_mask, order, node_zonelist(nid, gfp_mask)); } -- 2.39.5