Prevent multiple threads from executing the DumpDoneCallback handler...

chrome/app/breakpad_win.cc

 // Copyright (c) 2009 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 "chrome/app/breakpad_win.h"
 
 #include <windows.h>
 #include <shellapi.h>
 #include <tchar.h>
 #include <vector>
@@ skipping 116 matching lines @@
   return &custom_info_browser;
 }
 
 // Contains the information needed by the worker thread.
 struct CrashReporterInfo {
   google_breakpad::CustomClientInfo* custom_info;
   std::wstring dll_path;
   std::wstring process_type;
 };
 
+// flag to indicate that we are already handling an exception.
+volatile LONG handling_exception = 0;
+
 // This callback is executed when the browser process has crashed, after
 // the crash dump has been created. We need to minimize the amount of work
 // done here since we have potentially corrupted process. Our job is to
 // spawn another instance of chrome which will show a 'chrome has crashed'
 // dialog. This code needs to live in the exe and thus has no access to
 // facilities such as the i18n helpers.
 bool DumpDoneCallback(const wchar_t*, const wchar_t*, void*,
                       EXCEPTION_POINTERS* ex_info,
                       MDRawAssertionInfo*, bool) {
+  // Capture every thread except the first one in the sleep. We don't
+  // want multiple threads to concurrently execute the rest of the code.
+  if (::InterlockedCompareExchange(&handling_exception, 1, 0) == 1) {
+    ::Sleep(INFINITE);

[Nicolas Sylvain, 2009/10/16 22:58:46]

why not just return false?

[cpu_(ooo_6.6-7.5), 2009/10/17 00:54:19]

Because we are in the exception hander still so the first thread to return
causes the process to terminate.

+  }
+
   // If the exception is because there was a problem loading a delay-loaded
   // module, then show the user a dialog explaining the problem and then exit.
   if (DelayLoadFailureExceptionMessageBox(ex_info))
     return true;
 
   // We set CHROME_CRASHED env var. If the CHROME_RESTART is present.
   // This signals the child process to show the 'chrome has crashed' dialog.
   if (!::GetEnvironmentVariableW(env_vars::kRestartInfo, NULL, 0))
     return true;
   ::SetEnvironmentVariableW(env_vars::kShowRestart, L"1");
@@ skipping 209 matching lines @@
       if (QueueUserWorkItem(
               &InitCrashReporterThread,
               info.release(),
               WT_EXECUTELONGFUNCTION) == 0) {
         // We failed to queue to the worker pool, initialize in this thread.
         InitCrashReporterThread(info.release());
       }
     }
   }
 }