diff --git a/arch/x86/include/asm/timex.h b/arch/x86/include/asm/timex.h
index f5c2c982a24a..8ad16858b2e8 100644
--- a/arch/x86/include/asm/timex.h
+++ b/arch/x86/include/asm/timex.h
@@ -9,7 +9,7 @@
 * Fix for vmware installer failure to build vmmon and vmnet kernel modules
 * as random_get_entropy_fallback() is not found in this unit.
 */
-unsigned long random_get_entropy_fallback(void);
+extern unsigned long random_get_entropy_fallback(void);
 
 static inline unsigned long random_get_entropy(void)
 {