Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
@@ -356,11 +356,19 @@
   CHECK(module_name);
   const char *is_data_str = is_data ? "DATA " : "";
   if (arch == kModuleArchUnknown) {
-    internal_snprintf(buffer_, kBufferSize, "%s\"%s\" 0x%zx\n", is_data_str,
-                      module_name, module_offset);
+    if (internal_snprintf(buffer_, kBufferSize, "%s\"%s\" 0x%zx\n", is_data_str,
+                          module_name,
+                          module_offset) >= static_cast<int>(kBufferSize)) {
+      Report("WARNING: Command buffer too small");
+      return nullptr;
+    }
   } else {
-    internal_snprintf(buffer_, kBufferSize, "%s\"%s:%s\" 0x%zx\n", is_data_str,
-                      module_name, ModuleArchToString(arch), module_offset);
+    if (internal_snprintf(buffer_, kBufferSize, "%s\"%s:%s\" 0x%zx\n",
+                          is_data_str, module_name, ModuleArchToString(arch),
+                          module_offset) >= static_cast<int>(kBufferSize)) {
+      Report("WARNING: Command buffer too small");
+      return nullptr;
+    }
   }
   return symbolizer_process_->SendCommand(buffer_);
 }
@@ -426,6 +434,11 @@
     read_len += just_read;
     if (ReachedEndOfOutput(buffer, read_len))
       break;
+    if (read_len + 1 == max_length) {
+      Report("WARNING: Symbolizer buffer too small");
+      read_len = 0;
+      break;
+    }
   }
   buffer[read_len] = '\0';
   return true;
Index: compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
@@ -424,7 +424,6 @@
   InternalSymbolizer() { }
 
   static const int kBufferSize = 16 * 1024;
-  static const int kMaxDemangledNameSize = 1024;
   char buffer_[kBufferSize];
 };
 #else  // SANITIZER_SUPPORTS_WEAK_HOOKS
Index: compiler-rt/trunk/lib/sanitizer_common/symbolizer/sanitizer_symbolize.cc
===================================================================
--- compiler-rt/trunk/lib/sanitizer_common/symbolizer/sanitizer_symbolize.cc
+++ compiler-rt/trunk/lib/sanitizer_common/symbolizer/sanitizer_symbolize.cc
@@ -41,8 +41,8 @@
         getDefaultSymbolizer()->symbolizeInlinedCode(ModuleName, ModuleOffset);
     Printer << (ResOrErr ? ResOrErr.get() : llvm::DIInliningInfo());
   }
-  __sanitizer::internal_snprintf(Buffer, MaxLength, "%s", Result.c_str());
-  return true;
+  return __sanitizer::internal_snprintf(Buffer, MaxLength, "%s",
+                                        Result.c_str()) < MaxLength;
 }
 
 bool __sanitizer_symbolize_data(const char *ModuleName, uint64_t ModuleOffset,
@@ -55,8 +55,8 @@
         getDefaultSymbolizer()->symbolizeData(ModuleName, ModuleOffset);
     Printer << (ResOrErr ? ResOrErr.get() : llvm::DIGlobal());
   }
-  __sanitizer::internal_snprintf(Buffer, MaxLength, "%s", Result.c_str());
-  return true;
+  return __sanitizer::internal_snprintf(Buffer, MaxLength, "%s",
+                                        Result.c_str()) < MaxLength;
 }
 
 void __sanitizer_symbolize_flush() { getDefaultSymbolizer()->flush(); }
@@ -65,8 +65,10 @@
                                    int MaxLength) {
   std::string Result =
       llvm::symbolize::LLVMSymbolizer::DemangleName(Name, nullptr);
-  __sanitizer::internal_snprintf(Buffer, MaxLength, "%s", Result.c_str());
-  return static_cast<int>(Result.size() + 1);
+  return __sanitizer::internal_snprintf(Buffer, MaxLength, "%s",
+                                        Result.c_str()) < MaxLength
+             ? static_cast<int>(Result.size() + 1)
+             : 0;
 }
 
 }  // extern "C"
Index: compiler-rt/trunk/test/sanitizer_common/TestCases/symbolize_stack.cc
===================================================================
--- compiler-rt/trunk/test/sanitizer_common/TestCases/symbolize_stack.cc
+++ compiler-rt/trunk/test/sanitizer_common/TestCases/symbolize_stack.cc
@@ -0,0 +1,28 @@
+// RUN: %clangxx -O0 %s -o %t && %run %t 2>&1 | FileCheck %s
+
+// Test that symbolizer does not crash on frame with large function name.
+
+#include <sanitizer/common_interface_defs.h>
+#include <vector>
+
+template <int N> struct A {
+  template <class T> void RecursiveTemplateFunction(const T &t);
+};
+
+template <int N>
+template <class T>
+__attribute__((noinline)) void A<N>::RecursiveTemplateFunction(const T &) {
+  std::vector<T> t;
+  return A<N - 1>().RecursiveTemplateFunction(t);
+}
+
+template <>
+template <class T>
+__attribute__((noinline)) void A<0>::RecursiveTemplateFunction(const T &) {
+  __sanitizer_print_stack_trace();
+}
+
+int main() {
+  // CHECK: {{vector<.*vector<.*vector<.*vector<.*vector<}}
+  A<10>().RecursiveTemplateFunction(0);
+}