mm: sparsemem memory_present() fix

[sfrench/cifs-2.6.git] / mm / sparse.c

diff --git a/mm/sparse.c b/mm/sparse.c
index f6a43c09c322cdb39077392ec1c77e9904c52d82..98d6b39c34722c1734bee587a612ce0f74d7fbfa 100644 (file)
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -149,8 +149,18 @@ static inline int sparse_early_nid(struct mem_section *section)
 /* Record a memory area against a node. */
 void __init memory_present(int nid, unsigned long start, unsigned long end)
 {
+       unsigned long max_arch_pfn = 1UL << (MAX_PHYSMEM_BITS-PAGE_SHIFT);
        unsigned long pfn;
 
+       /*
+        * Sanity checks - do not allow an architecture to pass
+        * in larger pfns than the maximum scope of sparsemem:
+        */
+       if (start >= max_arch_pfn)
+               return;
+       if (end >= max_arch_pfn)
+               end = max_arch_pfn;
+
        start &= PAGE_SECTION_MASK;
        for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) {
                unsigned long section = pfn_to_section_nr(pfn);