diff --git a/common.h b/common.h
index 999a40e..00c3483 100644
--- a/common.h
+++ b/common.h
@@ -13,6 +13,12 @@
 
 #define offsetof(type, member) ((size_t)&(((type*)0)->member))
 
+#define PANIC(fmt, ...) \
+    do { \
+        printf("panic %s:%d" fmt "\n", __FILE__, __LINE__, ## __VAR_ARGS__); \
+        while(1){}; \
+    } while(0)
+
 typedef int bool;
 typedef unsigned char uint8_t;
 typedef unsigned short uint16_t ;