diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index e6e95a9f07a5..b18759a673c6 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -916,6 +916,24 @@ perf_trace_buf_submit(void *raw_data, int size, int rctx, u16 type,
 
 #endif
 
+#define TRACE_EVENT_STR_MAX	512
+
+/*
+ * gcc warns that you can not use a va_list in an inlined
+ * function. But lets me make it into a macro :-/
+ */
+#define __trace_event_vstr_len(fmt, va)			\
+({							\
+	va_list __ap;					\
+	int __ret;					\
+							\
+	va_copy(__ap, *(va));				\
+	__ret = vsnprintf(NULL, 0, fmt, __ap) + 1;	\
+	va_end(__ap);					\
+							\
+	min(__ret, TRACE_EVENT_STR_MAX);		\
+})
+
 #endif /* _LINUX_TRACE_EVENT_H */
 
 /*
diff --git a/include/trace/stages/stage1_struct_define.h b/include/trace/stages/stage1_struct_define.h
index a16783419687..1b7bab60434c 100644
--- a/include/trace/stages/stage1_struct_define.h
+++ b/include/trace/stages/stage1_struct_define.h
@@ -26,6 +26,9 @@
 #undef __string_len
 #define __string_len(item, src, len) __dynamic_array(char, item, -1)
 
+#undef __vstring
+#define __vstring(item, fmt, ap) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(char, item, -1)
 
diff --git a/include/trace/stages/stage2_data_offsets.h b/include/trace/stages/stage2_data_offsets.h
index 42fd1e8813ec..1b7a8f764fdd 100644
--- a/include/trace/stages/stage2_data_offsets.h
+++ b/include/trace/stages/stage2_data_offsets.h
@@ -32,6 +32,9 @@
 #undef __string_len
 #define __string_len(item, src, len) __dynamic_array(char, item, -1)
 
+#undef __vstring
+#define __vstring(item, fmt, ap) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
 
diff --git a/include/trace/stages/stage4_event_fields.h b/include/trace/stages/stage4_event_fields.h
index e80cdc397a43..c3790ec7a453 100644
--- a/include/trace/stages/stage4_event_fields.h
+++ b/include/trace/stages/stage4_event_fields.h
@@ -38,6 +38,9 @@
 #undef __string_len
 #define __string_len(item, src, len) __dynamic_array(char, item, -1)
 
+#undef __vstring
+#define __vstring(item, fmt, ap) __dynamic_array(char, item, -1)
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)
 
diff --git a/include/trace/stages/stage5_get_offsets.h b/include/trace/stages/stage5_get_offsets.h
index 7ee5931300e6..fba4c24ed9e6 100644
--- a/include/trace/stages/stage5_get_offsets.h
+++ b/include/trace/stages/stage5_get_offsets.h
@@ -39,6 +39,10 @@
 #undef __string_len
 #define __string_len(item, src, len) __dynamic_array(char, item, (len) + 1)
 
+#undef __vstring
+#define __vstring(item, fmt, ap) __dynamic_array(char, item,		\
+		      __trace_event_vstr_len(fmt, ap))
+
 #undef __rel_dynamic_array
 #define __rel_dynamic_array(type, item, len)				\
 	__item_length = (len) * sizeof(type);				\
diff --git a/include/trace/stages/stage6_event_callback.h b/include/trace/stages/stage6_event_callback.h
index e1724f73594b..0f51f6b3ab70 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -24,6 +24,9 @@
 #undef __string_len
 #define __string_len(item, src, len) __dynamic_array(char, item, -1)
 
+#undef __vstring
+#define __vstring(item, fmt, ap) __dynamic_array(char, item, -1)
+
 #undef __assign_str
 #define __assign_str(dst, src)						\
 	strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)");
@@ -35,6 +38,10 @@
 		__get_str(dst)[len] = '\0';				\
 	} while(0)
 
+#undef __assign_vstr
+#define __assign_vstr(dst, fmt, va)					\
+	vsnprintf(__get_str(dst), TRACE_EVENT_STR_MAX, fmt, *(va))
+
 #undef __bitmask
 #define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1)