On Fri, Jan 10, 2014 at 10:29:06PM +0000, Mark Salter wrote:

+void __init create_id_mapping(phys_addr_t addr, phys_addr_t size)
+{
+	pgd_t *pgd = &idmap_pg_dir[pgd_index(addr)];
+
+	if (pgd >= &idmap_pg_dir[ARRAY_SIZE(idmap_pg_dir)]) {
+		pr_warn("BUG: not creating id mapping for 0x%016llx\n", addr);
+		return;
+	}

The condition above is always false since pgd_index() already ands the
index with (PTRS_PER_PGD - 1). Better check addr against something like
(PTRS_PER_PGD * PGDIR_SIZE) (for clarity, you could do other shifts,
doesn't really matter).

-- 
Catalin