diff --git a/arch/ia64/sn/kernel/setup.c b/arch/ia64/sn/kernel/setup.c
index 53b01b8e2f197129819c4a8f937073556a9690c0..36182c84363ce914d15f34a5be72afdc6f580b46 100644
--- a/arch/ia64/sn/kernel/setup.c
+++ b/arch/ia64/sn/kernel/setup.c
@@ -579,7 +579,7 @@ void sn_cpu_init(void)
 		       (sn_prom_type == 1) ? "real" : "fake");
 	}
 
-	memset(pda, 0, sizeof(pda));
+	memset(pda, 0, sizeof(*pda));
 	if (ia64_sn_get_sn_info(0, &sn_hub_info->shub2,
 				&sn_hub_info->nasid_bitmask,
 				&sn_hub_info->nasid_shift,