diff --git a/src/trace.c b/src/trace.c
index 9b5080c7..acb35408 100644
--- a/src/trace.c
+++ b/src/trace.c
@@ -272,7 +272,7 @@ static void _tf_trace_begin_tagged(tf_trace_t* trace, const char* name, void* ta
 
 	char line[1024];
 	int p = snprintf(line, sizeof(line), "{\"ph\": \"B\", \"pid\": %d, \"tid\": %" PRId64 ", \"ts\": %" PRId64 ", \"name\": \"", getpid(), (int64_t)self, _trace_ts());
-	p += _tf_trace_escape_name(line + p, sizeof(line) - p, name);
+	p += _tf_trace_escape_name(line + p, sizeof(line) - p - 4, name);
 	p += snprintf(line + p, sizeof(line) - p, "\"},");
 	p = tf_min(p, tf_countof(line));
 	trace->callback(trace, line, p, trace->user_data);
@@ -299,7 +299,7 @@ static void _tf_trace_end_tagged(tf_trace_t* trace, void* tag)
 
 	char line[1024];
 	int p = snprintf(line, sizeof(line), "{\"ph\": \"E\", \"pid\": %d, \"tid\": %" PRId64 ", \"ts\": %" PRId64 ", \"name\": \"", getpid(), (int64_t)pthread_self(), _trace_ts());
-	p += _tf_trace_escape_name(line + p, sizeof(line) - p, name);
+	p += _tf_trace_escape_name(line + p, sizeof(line) - p - 4, name);
 	p += snprintf(line + p, sizeof(line) - p, "\"},");
 	p = tf_min(p, tf_countof(line));
 	trace->callback(trace, line, p, trace->user_data);