diff --git a/runtime/platform/text_buffer.cc b/runtime/platform/text_buffer.cc
index b1ef63ac679..ec42113fd1e 100644
--- a/runtime/platform/text_buffer.cc
+++ b/runtime/platform/text_buffer.cc
@@ -135,12 +135,7 @@ void TextBuffer::AddEscapedString(const char* s) {
 void TextBuffer::EnsureCapacity(intptr_t len) {
   intptr_t remaining = buf_size_ - msg_len_;
   if (remaining <= len) {
-    const int kBufferSpareCapacity = 64;  // Somewhat arbitrary.
-    // TODO(turnidge): do we need to guard against overflow or other
-    // security issues here? Text buffers are used by the debugger
-    // to send user-controlled data (e.g. values of string variables) to
-    // the debugger front-end.
-    intptr_t new_size = buf_size_ + len + kBufferSpareCapacity;
+    intptr_t new_size = buf_size_ + Utils::Maximum(buf_size_, len);
     char* new_buf = reinterpret_cast<char*>(realloc(buf_, new_size));
     if (new_buf == NULL) {
       OUT_OF_MEMORY();
diff --git a/runtime/vm/compilation_trace.cc b/runtime/vm/compilation_trace.cc
index 29cdfa2077a..4c4db1e7222 100644
--- a/runtime/vm/compilation_trace.cc
+++ b/runtime/vm/compilation_trace.cc
@@ -20,7 +20,7 @@ namespace dart {
 DEFINE_FLAG(bool, trace_compilation_trace, false, "Trace compilation trace.");
 
 CompilationTraceSaver::CompilationTraceSaver(Zone* zone)
-    : buf_(zone, 4 * KB),
+    : buf_(zone, 1 * MB),
       func_name_(String::Handle(zone)),
       cls_(Class::Handle(zone)),
       cls_name_(String::Handle(zone)),
diff --git a/runtime/vm/zone_text_buffer.cc b/runtime/vm/zone_text_buffer.cc
index 5754b115509..8d3032bca9d 100644
--- a/runtime/vm/zone_text_buffer.cc
+++ b/runtime/vm/zone_text_buffer.cc
@@ -50,12 +50,7 @@ void ZoneTextBuffer::AddString(const char* s) {
 void ZoneTextBuffer::EnsureCapacity(intptr_t len) {
   intptr_t remaining = capacity_ - length_;
   if (remaining <= len) {
-    const int kBufferSpareCapacity = 64;  // Somewhat arbitrary.
-    // TODO(turnidge): do we need to guard against overflow or other
-    // security issues here? Text buffers are used by the debugger
-    // to send user-controlled data (e.g. values of string variables) to
-    // the debugger front-end.
-    intptr_t new_capacity = capacity_ + len + kBufferSpareCapacity;
+    intptr_t new_capacity = capacity_ + Utils::Maximum(capacity_, len);
     buffer_ = zone_->Realloc<char>(buffer_, capacity_, new_capacity);
     capacity_ = new_capacity;
   }