diff --git a/src/trace.c b/src/trace.c
index f7dcb183..1aa89323 100644
--- a/src/trace.c
+++ b/src/trace.c
@@ -5,6 +5,7 @@
 #include "trace.h"
 
 #include "mem.h"
+#include "util.js.h"
 
 #include "sqlite3.h"
 #include "uv.h"
@@ -138,7 +139,7 @@ void tf_trace_counter(tf_trace_t* trace, const char* name, int argc, const char*
 	{
 		p += snprintf(line + p, sizeof(line) - p, "\"%s\": %" PRId64 "%s", arg_names[i], arg_values[i], i == argc - 1 ? "}}," : ", ");
 	}
-
+	p = tf_min(p, _countof(line));
 	trace->callback(trace, line, p, trace->user_data);
 }
 
@@ -279,6 +280,7 @@ static void _tf_trace_begin_tagged(tf_trace_t* trace, const char* name, void* ta
 	int p = snprintf(line, sizeof(line), "{\"ph\": \"B\", \"pid\": %d, \"tid\": \"0x%" PRIx64 "\", \"ts\": %" PRId64 ", \"name\": \"", getpid(), (int64_t)self, _trace_ts());
 	p += _tf_trace_escape_name(line + p, sizeof(line) - p, name);
 	p += snprintf(line + p, sizeof(line) - p, "\"},");
+	p = tf_min(p, _countof(line));
 	trace->callback(trace, line, p, trace->user_data);
 }
 
@@ -305,6 +307,7 @@ static void _tf_trace_end_tagged(tf_trace_t* trace, void* tag)
 	int p = snprintf(line, sizeof(line), "{\"ph\": \"E\", \"pid\": %d, \"tid\": \"0x%" PRIx64 "\", \"ts\": %" PRId64 ", \"name\": \"", getpid(), (int64_t)pthread_self(), _trace_ts());
 	p += _tf_trace_escape_name(line + p, sizeof(line) - p, name);
 	p += snprintf(line + p, sizeof(line) - p,  "\"},");
+	p = tf_min(p, _countof(line));
 	trace->callback(trace, line, p, trace->user_data);
 }
 
diff --git a/src/util.js.h b/src/util.js.h
index d616fea9..5b27e6db 100644
--- a/src/util.js.h
+++ b/src/util.js.h
@@ -22,4 +22,4 @@ const char* tf_util_backtrace_string();
 
 const char* tf_util_function_to_string(void* function);
 
-#define tf_min(a, b) ({ __typeof__ (a) _a = (a); __typeof__ (b) _b = (b);  _a > _b ? _a : _b; })
+#define tf_min(a, b) ({ __typeof__ (a) _a = (a); __typeof__ (b) _b = (b);  _a > _b ? _b : _a; })