diff --git a/README.md b/README.md
index ed9e4b4..e594045 100644
--- a/README.md
+++ b/README.md
@@ -24,5 +24,11 @@ LDD-LinuxDeviceDrivers
 
 
 
+#3  TODOLIST--目前在完成的工作
+-------
 
-
+| 任务 | 描述 |
+|:----:|:----:|
+| study/debug                   | 内核调试工具集锦, 包括debugfs, trace, gdb, systemtap 的介绍和使用     |
+| study/pattern                 | 内核设计的奇技淫巧, 介绍内核中使用的一些高级语法技巧和设计思路        |
+| study/kernel/data_structure   | 介绍内核中提供的数据结构的用法                                        |
diff --git a/study/pattern/build_bug_on/userspace/Makefile b/study/pattern/build_bug_on/userspace/Makefile
index 70c4199..814894e 100644
--- a/study/pattern/build_bug_on/userspace/Makefile
+++ b/study/pattern/build_bug_on/userspace/Makefile
@@ -1,5 +1,5 @@
 CFLAGS = -std=gnu99
-target=not_power_of_2 zero
+target=not_power_of_2 zero null
 
 all:$(target)
 
@@ -12,19 +12,19 @@ zero : build_bug_on_zero.o
 	@echo "BUILD_BUG_ON_ZERO..."
 
 
-SCClient : SCClient.o
+null : build_bug_on_null.o
 	$(CC) $^ -o $@ $(LDFLAGS) -lpthread
-	@echo "简单的模拟高并发的客户端..."
+	@echo "BUILD_BUG_ON_NULL..."
 
-SCMClient : SCMClient.o
+invalid : build_bug_on_invalid.o
 	$(CC) $^ -o $@ $(LDFLAGS) -lpthread
-	@echo "带线程锁的模拟高并发的客户端..."
+	@echo "BUILD_BUG_ON_INVALID..."
 
 %.o : %.c
-	-$(CC) -c $^ -o $@  $(CFLAGS) $(DEFINES)
+	$(CC) -c $^ -o $@  $(CFLAGS) $(DEFINES)
 
 %.o	: %.cpp
-	-$(CXX) -c $^ -o $@  $(CFLAGS) $(DEFINES)
+	$(CXX) -c $^ -o $@  $(CFLAGS) $(DEFINES)
 
 clean :
 	rm -rf *.o
diff --git a/study/pattern/build_bug_on/userspace/build_bug_on_invalid.c b/study/pattern/build_bug_on/userspace/build_bug_on_invalid.c
new file mode 100644
index 0000000..f9b9a7e
--- /dev/null
+++ b/study/pattern/build_bug_on/userspace/build_bug_on_invalid.c
@@ -0,0 +1,34 @@
+/*************************************************************************
+    > File Name: build_bug_on_invalid.c
+    > Author: GatieMe
+    > Mail: gatieme@163.com
+    > Created Time: Thu 13 Apr 2017 11:26:18 AM CST
+ ************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+#include "bug.h"
+
+# define __force        __attribute__((force))
+
+#ifndef BUILD_BUG_ON_INVALID
+/*
+ * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
+ * expression but avoids the generation of any code, even if that expression
+ * has side-effects.
+ */
+#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
+#endif
+
+
+#define NUM 12_$
+int main(int argc, char *argv[])
+{
+    BUILD_BUG_ON_INVALID(NUM);
+
+	return EXIT_SUCCESS;
+}
+
+
diff --git a/study/pattern/build_bug_on/userspace/build_bug_on_null.c b/study/pattern/build_bug_on/userspace/build_bug_on_null.c
new file mode 100644
index 0000000..a10b4ef
--- /dev/null
+++ b/study/pattern/build_bug_on/userspace/build_bug_on_null.c
@@ -0,0 +1,26 @@
+/*************************************************************************
+    > File Name: build_bug_on_null.c
+    > Author: GatieMe
+    > Mail: gatieme@163.com
+    > Created Time: Thu 13 Apr 2017 11:20:31 AM CST
+ ************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+
+#include "bug.h"
+
+#ifndef BUILD_BUG_ON_NULL
+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
+#endif
+
+#define POINT  !(NULL)
+int main(int argc, char *argv[])
+{
+    BUILD_BUG_ON_NULL(POINT);
+
+	return EXIT_SUCCESS;
+}
+
+
diff --git a/study/pattern/build_bug_on/userspace/null b/study/pattern/build_bug_on/userspace/null
new file mode 100755
index 0000000..5ef92a0
Binary files /dev/null and b/study/pattern/build_bug_on/userspace/null differ