GTTF: Make Linux stack dump signal handler async-signal safe.

base/debug/stack_trace_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <limits>
 #include <sstream>
 #include <string>
 
 #include "base/debug/stack_trace.h"
 #include "base/logging.h"
+#include "base/process_util.h"
+#include "base/test/multiprocess_test.h"
+#include "base/test/test_timeouts.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "testing/multiprocess_func_list.h"
 
 namespace base {
 namespace debug {
 
+typedef MultiProcessTest StackTraceTest;
+
 // Note: On Linux, this test currently only fully works on Debug builds.
 // See comments in the #ifdef soup if you intend to change this.
 #if defined(OS_WIN)
 // Always fails on Windows: crbug.com/32070
 #define MAYBE_OutputToStream DISABLED_OutputToStream
 #else
 #define MAYBE_OutputToStream OutputToStream
 #endif
-TEST(StackTrace, MAYBE_OutputToStream) {
+TEST_F(StackTraceTest, MAYBE_OutputToStream) {
   StackTrace trace;
 
   // Dump the trace into a string.
   std::ostringstream os;
   trace.OutputToStream(&os);
   std::string backtrace_message = os.str();
 
   // ToString() should produce the same output.
   EXPECT_EQ(backtrace_message, trace.ToString());
 
@@ skipping 28 matching lines @@
   // which should be the first symbol in the trace.
   //
   // TODO(port): Find a more reliable way to resolve symbols.
 
   // Expect to at least find main.
   EXPECT_TRUE(backtrace_message.find("start") != std::string::npos)
       << "Expected to find start in backtrace:\n"
       << backtrace_message;
 
 #endif
-#elif defined(__GLIBCXX__)
+#elif defined(USE_SYMBOLIZE)
   // This branch is for gcc-compiled code, but not Mac due to the
   // above #if.
   // Expect a demangled symbol.
   EXPECT_TRUE(backtrace_message.find("testing::Test::Run()") !=
               std::string::npos)
       << "Expected a demangled symbol in backtrace:\n"
       << backtrace_message;
 
 #elif 0
   // This is the fall-through case; it used to cover Windows.
@@ skipping 13 matching lines @@
 
   // Expect to find this function as well.
   // Note: This will fail if not linked with -rdynamic (aka -export_dynamic)
   EXPECT_TRUE(backtrace_message.find(__func__) != std::string::npos)
       << "Expected to find " << __func__ << " in backtrace:\n"
       << backtrace_message;
 
 #endif  // define(OS_MACOSX)
 }
 
+MULTIPROCESS_TEST_MAIN(MismatchedMallocChildProcess) {
+  char* pointer = new char[10];
+  delete pointer;
+  return 2;
+}
+
+// Regression test for StackDumpingSignalHandler async-signal unsafety.
+// Combined with tcmalloc's debugallocation, that signal handler
+// and e.g. mismatched new[]/delete would cause a hang because
+// of re-entering malloc.
+TEST_F(StackTraceTest, AsyncSignalUnsafeSignalHandlerHang) {
+  ProcessHandle child = this->SpawnChild("MismatchedMallocChildProcess", false);
+  ASSERT_NE(kNullProcessHandle, child);
+  ASSERT_TRUE(WaitForSingleProcess(child, TestTimeouts::action_timeout()));
+}
+
 // The test is used for manual testing, e.g., to see the raw output.
-TEST(StackTrace, DebugOutputToStream) {
+TEST_F(StackTraceTest, DebugOutputToStream) {
   StackTrace trace;
   std::ostringstream os;
   trace.OutputToStream(&os);
   VLOG(1) << os.str();
 }
 
 // The test is used for manual testing, e.g., to see the raw output.
-TEST(StackTrace, DebugPrintBacktrace) {
+TEST_F(StackTraceTest, DebugPrintBacktrace) {
   StackTrace().PrintBacktrace();
 }
 
+namespace {
+
+std::string itoa_r_wrapper(intptr_t i, size_t sz, int base) {
+  char buffer[1024];
+  CHECK_LE(sz, sizeof(buffer));
+
+  char* result = internal::itoa_r(i, buffer, sz, base);
+  EXPECT_TRUE(result);
+  return std::string(buffer);
+}
+
+}  // namespace
+
+#if defined(OS_POSIX)
+TEST_F(StackTraceTest, itoa_r) {
+  EXPECT_EQ("0", itoa_r_wrapper(0, 128, 10));
+  EXPECT_EQ("-1", itoa_r_wrapper(-1, 128, 10));

[jar (doing other things), 2012/11/07 00:32:07]

You should do this base 16, and get (on your 64 bit machine):

"FFFFFFFFFFFFFFFF"

+
+  // Test edge cases.
+  EXPECT_EQ("-9223372036854775808",

[jar (doing other things), 2012/11/07 00:32:07]

On a 32 bit machine, this will give a different answer.  You can base it in
sizeof(intptr_t).

[Paweł Hajdan Jr., 2012/11/07 00:52:28]

Do we have any 32-bit machines we test on? In case a trybot or buildbot fails on
this I'm defnitely going to add 32-bit case.

[Scott Hess - ex-Googler, 2012/11/07 01:02:26]

OSX still builds 32-bit.

+            itoa_r_wrapper(std::numeric_limits<intptr_t>::min(), 128, 10));
+  EXPECT_EQ("9223372036854775807",
+            itoa_r_wrapper(std::numeric_limits<intptr_t>::max(), 128, 10));

[jar (doing other things), 2012/11/07 00:32:07]

Also do this verification, base 16.  The results should be (on your 64 bit
machine):

max ==> "7FFFFFFFFFFFFFFF"

min==> "8000000000000000"

Again, results will vary depending on word size. There should be no 

+
+  // Test hex output.
+  EXPECT_EQ("688", itoa_r_wrapper(0x688, 128, 16));
+  EXPECT_EQ("deadbeef", itoa_r_wrapper(0xdeadbeef, 128, 16));
+
+  // Check that itoa_r respects passed buffer size limit.
+  char buffer[1024];
+  EXPECT_TRUE(internal::itoa_r(0xdeadbeef, buffer, 10, 16));
+  EXPECT_TRUE(internal::itoa_r(0xdeadbeef, buffer, 9, 16));
+  EXPECT_FALSE(internal::itoa_r(0xdeadbeef, buffer, 8, 16));
+  EXPECT_FALSE(internal::itoa_r(0xdeadbeef, buffer, 7, 16));
+}
+#endif  // defined(OS_POSIX)
+
 }  // namespace debug
 }  // namespace base