diff --git a/tools/include/linux/kernel.h b/tools/include/linux/kernel.h
index 3e8df500cfbd4..9701e8307db02 100644
--- a/tools/include/linux/kernel.h
+++ b/tools/include/linux/kernel.h
@@ -92,7 +92,9 @@ int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
 int scnprintf(char * buf, size_t size, const char * fmt, ...);
 int scnprintf_pad(char * buf, size_t size, const char * fmt, ...);
 
+#ifndef ARRAY_SIZE
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
+#endif
 
 #define current_gfp_context(k) 0
 #define synchronize_rcu()
diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index 8d50483fe204a..f1180987492c9 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -48,6 +48,10 @@
 #include <stdarg.h>
 #include <stdio.h>
 
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+#endif
+
 /* define kselftest exit codes */
 #define KSFT_PASS  0
 #define KSFT_FAIL  1
diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h
index 79a182cfa43ad..471eaa7b3a3f2 100644
--- a/tools/testing/selftests/kselftest_harness.h
+++ b/tools/testing/selftests/kselftest_harness.h
@@ -671,7 +671,9 @@
 #define EXPECT_STRNE(expected, seen) \
 	__EXPECT_STR(expected, seen, !=, 0)
 
+#ifndef ARRAY_SIZE
 #define ARRAY_SIZE(a)	(sizeof(a) / sizeof(a[0]))
+#endif
 
 /* Support an optional handler after and ASSERT_* or EXPECT_*.  The approach is
  * not thread-safe, but it should be fine in most sane test scenarios.