diff --git a/drivers/acpi/acpica/utprint.c b/drivers/acpi/acpica/utprint.c
index a874dac7db5cc9ec46b97b422826d8506c15be62..681c11f4af4e89ed2d1f8e02b6c89244fa2646be 100644
--- a/drivers/acpi/acpica/utprint.c
+++ b/drivers/acpi/acpica/utprint.c
@@ -332,7 +332,12 @@ int vsnprintf(char *string, acpi_size size, const char *format, va_list args)
 	int i;
 
 	pos = string;
-	end = string + size;
+
+	if (size != ACPI_UINT32_MAX) {
+		end = string + size;
+	} else {
+		end = ACPI_CAST_PTR(char, ACPI_UINT32_MAX);
+	}
 
 	for (; *format; ++format) {
 		if (*format != '%') {