diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index acc17194c160..08810a463880 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -102,6 +102,9 @@ TRACE_MAKE_SYSTEM_STR();
 #undef __string
 #define __string(item, src) __dynamic_array(char, item, -1)
 
+#undef __string_len
+#define __string_len(item, src, len) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)
 
@@ -197,6 +200,9 @@ TRACE_MAKE_SYSTEM_STR();
 #undef __string
 #define __string(item, src) __dynamic_array(char, item, -1)
 
+#undef __string_len
+#define __string_len(item, src, len) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
 
@@ -459,6 +465,9 @@ static struct trace_event_functions trace_event_type_funcs_##call = {	\
 #undef __string
 #define __string(item, src) __dynamic_array(char, item, -1)
 
+#undef __string_len
+#define __string_len(item, src, len) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
 
@@ -507,6 +516,9 @@ static struct trace_event_fields trace_event_fields_##call[] = {	\
 #define __string(item, src) __dynamic_array(char, item,			\
 		    strlen((src) ? (const char *)(src) : "(null)") + 1)
 
+#undef __string_len
+#define __string_len(item, src, len) __dynamic_array(char, item, (len) + 1)
+
 /*
  * __bitmask_size_in_bytes_raw is the number of bytes needed to hold
  * num_possible_cpus().
@@ -670,10 +682,20 @@ static inline notrace int trace_event_get_offsets_##call(		\
 #undef __string
 #define __string(item, src) __dynamic_array(char, item, -1)
 
+#undef __string_len
+#define __string_len(item, src, len) __dynamic_array(char, item, -1)
+
 #undef __assign_str
 #define __assign_str(dst, src)						\
 	strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)");
 
+#undef __assign_str_len
+#define __assign_str_len(dst, src, len)					\
+	do {								\
+		memcpy(__get_str(dst), (src), (len));			\
+		__get_str(dst)[len] = '\0';				\
+	} while(0)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
 
diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h
index 13a35f7cbe66..e61471ab7d14 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -141,6 +141,33 @@
  *         In most cases, the __assign_str() macro will take the same
  *         parameters as the __string() macro had to declare the string.
  *
+ *   __string_len: This is a helper to a __dynamic_array, but it understands
+ *	   that the array has characters in it, and with the combined
+ *         use of __assign_str_len(), it will allocate 'len' + 1 bytes
+ *         in the ring buffer and add a '\0' to the string. This is
+ *         useful if the string being saved has no terminating '\0' byte.
+ *         It requires that the length of the string is known as it acts
+ *         like a memcpy().
+ *
+ *         Declared with:
+ *
+ *         __string_len(foo, bar, len)
+ *
+ *         To assign this string, use the helper macro __assign_str_len().
+ *
+ *         __assign_str(foo, bar, len);
+ *
+ *         Then len + 1 is allocated to the ring buffer, and a nul terminating
+ *         byte is added. This is similar to:
+ *
+ *         memcpy(__get_str(foo), bar, len);
+ *         __get_str(foo)[len] = 0;
+ *
+ *        The advantage of using this over __dynamic_array, is that it
+ *        takes care of allocating the extra byte on the ring buffer
+ *        for the '\0' terminating byte, and __get_str(foo) can be used
+ *        in the TP_printk().
+ *
  *   __bitmask: This is another kind of __dynamic_array, but it expects
  *         an array of longs, and the number of bits to parse. It takes
  *         two parameters (name, nr_bits), where name is the name of the