diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index 240a24400976929c663b9b3f8ce8bafa36435d5f..7c3f98ba4afefd00686fffc36283ad783a3e4798 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -173,7 +173,7 @@ static int param_set_trace_state(const char *val, struct kernel_param *kp)
 {
 	int result = 0;
 
-	if (!strncmp(val, "enable", strlen("enable"))) {
+	if (!strncmp(val, "enable", sizeof("enable") - 1)) {
 		result = acpi_debug_trace(trace_method_name, trace_debug_level,
 					  trace_debug_layer, 0);
 		if (result)
@@ -181,7 +181,7 @@ static int param_set_trace_state(const char *val, struct kernel_param *kp)
 		goto exit;
 	}
 
-	if (!strncmp(val, "disable", strlen("disable"))) {
+	if (!strncmp(val, "disable", sizeof("disable") - 1)) {
 		int name = 0;
 		result = acpi_debug_trace((char *)&name, trace_debug_level,
 					  trace_debug_layer, 0);