SyzyASAN: Block for crash handler startup as temporary workaround for startup hang

chrome/app/chrome_exe_main_win.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 <windows.h>
 #include <malloc.h>
 #include <shellscalingapi.h>
 #include <stddef.h>
 #include <tchar.h>
 
@@ skipping 189 matching lines @@
 
 #if !defined(WIN_CONSOLE_APP)
 int APIENTRY wWinMain(HINSTANCE instance, HINSTANCE prev, wchar_t*, int) {
 #else
 int main() {
   HINSTANCE instance = GetModuleHandle(nullptr);
 #endif
   install_static::InstallDetails::InitializeFromPrimaryModule(
       chrome::kChromeElfDllName);
 
+#if defined(SYZYASAN)
+  // This is a temporary workaround for a race during startup with the
+  // syzyasan_rtl.dll. See https://crbug.com/675710.
+  HMODULE chrome_elf = GetModuleHandle(chrome::kChromeElfDllName);

[Sigurður Ásgeirsson, 2016/12/20 20:42:47]

Stoopid question: why don't we simply link against chrome_elf's exports?

[scottmg, 2016/12/20 20:51:45]

Yuck, I have no idea. We probably do here actually. I think in other places it's
because the code runs in e.g. browser_tests which doesn't load chrome_elf.

+  auto block_until_handler_started = reinterpret_cast<void (*)()>(
+      GetProcAddress(chrome_elf, "BlockUntilHandlerStartedImpl"));
+  block_until_handler_started();
+#endif  // SYZYASAN
+
   // Initialize the CommandLine singleton from the environment.
   base::CommandLine::Init(0, nullptr);
   const base::CommandLine* command_line =
       base::CommandLine::ForCurrentProcess();
 
   const std::string process_type =
       command_line->GetSwitchValueASCII(switches::kProcessType);
 
   // Confirm that an explicit prefetch profile is used for all process types
   // except for the browser process. Any new process type will have to assign
@@ skipping 23 matching lines @@
   RemoveAppCompatFlagsEntry();
 
   // Load and launch the chrome dll. *Everything* happens inside.
   VLOG(1) << "About to load main DLL.";
   MainDllLoader* loader = MakeMainDllLoader();
   int rc = loader->Launch(instance, exe_entry_point_ticks);
   loader->RelaunchChromeBrowserWithNewCommandLineIfNeeded();
   delete loader;
   return rc;
 }