Track and cap thread creation

This is to help track down some crashes we're seeing with massive numbers of threads.

Review URL: https://chromiumcodereview.appspot.com/10928207

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@156923 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 41 insertions, 0 deletions

diff --git a/chrome/app/chrome_exe_main_win.cc b/chrome/app/chrome_exe_main_win.cc
index 237784d..f82f361 100644
--- a/chrome/app/chrome_exe_main_win.cc
+++ b/chrome/app/chrome_exe_main_win.cc
@@ -14,6 +14,43 @@
 #include "content/public/common/result_codes.h"
 #include "sandbox/win/src/sandbox_factory.h"
 
+namespace {
+
+// TODO(jschuh): Remove this after we narrow down the cause of the crashes.
+class ThreadTracker {
+ public:
+  static void NTAPI UpdateCount(PVOID module, DWORD reason, PVOID reserved) {
+    if (reason == DLL_THREAD_ATTACH) {
+      if (::InterlockedIncrement(&count_) > cap_)
+        __debugbreak();
+    } else if (reason == DLL_THREAD_DETACH) {
+      ::InterlockedDecrement(&count_);
+    }
+  }
+
+  static void SetCap(LONG cap) { cap_ = cap; }
+
+ private:
+  static LONG volatile count_;
+  static LONG volatile cap_;
+};
+
+LONG volatile ThreadTracker::count_ = 1;
+LONG volatile ThreadTracker::cap_ = LONG_MAX;
+
+}  // namespace
+
+// Magic required to get our function called on thread attach and detach.
+extern "C" {
+#pragma data_seg(push, old_seg)
+#pragma data_seg(".CRT$XLB")
+PIMAGE_TLS_CALLBACK p_thread_callback = ThreadTracker::UpdateCount;
+#pragma data_seg(pop, old_seg)
+
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#pragma comment(linker, "/INCLUDE:_p_thread_callback")
+}
+
 int RunChrome(HINSTANCE instance) {
   bool exit_now = true;
   // We restarted because of a previous crash. Ask user if we should relaunch.
@@ -26,6 +63,10 @@ int RunChrome(HINSTANCE instance) {
   sandbox::SandboxInterfaceInfo sandbox_info = {0};
   content::InitializeSandboxInfo(&sandbox_info);
 
+  // Cap the threads for any sandboxed process.
+  if (sandbox_info.target_services)
+    ThreadTracker::SetCap(200);
+
   // Load and launch the chrome dll. *Everything* happens inside.
   MainDllLoader* loader = MakeMainDllLoader();
   int rc = loader->Launch(instance, &sandbox_info);