diff --git a/sys/compat/linuxkpi/common/include/linux/math64.h b/sys/compat/linuxkpi/common/include/linux/math64.h
index 9b22416a9e9..dacba7dbae9 100644
--- a/sys/compat/linuxkpi/common/include/linux/math64.h
+++ b/sys/compat/linuxkpi/common/include/linux/math64.h
@@ -84,4 +84,11 @@ div_u64(uint64_t dividend, uint32_t divisor)
 	return (dividend / divisor);
 }
 
+static inline uint64_t
+mul_u32_u32(uint32_t a, uint32_t b)
+{
+
+	return ((uint64_t)a * b);
+}
+
 #endif /* _LINUX_MATH64_H */