Index: compiler-rt/trunk/lib/asan/asan_rtl.cc
===================================================================
--- compiler-rt/trunk/lib/asan/asan_rtl.cc
+++ compiler-rt/trunk/lib/asan/asan_rtl.cc
@@ -545,10 +545,18 @@
 void NOINLINE __asan_handle_no_return() {
   int local_stack;
   AsanThread *curr_thread = GetCurrentThread();
-  CHECK(curr_thread);
   uptr PageSize = GetPageSizeCached();
-  uptr top = curr_thread->stack_top();
-  uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
+  uptr top, bottom;
+  if (curr_thread) {
+    top = curr_thread->stack_top();
+    bottom = ((uptr)&local_stack - PageSize) & ~(PageSize - 1);
+  } else {
+    // If we haven't seen this thread, try asking the OS for stack bounds.
+    uptr tls_addr, tls_size, stack_size;
+    GetThreadStackAndTls(/*main=*/false, &bottom, &stack_size, &tls_addr,
+                         &tls_size);
+    top = bottom + stack_size;
+  }
   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
   if (top - bottom > kMaxExpectedCleanupSize) {
     static bool reported_warning = false;
@@ -564,7 +572,7 @@
     return;
   }
   PoisonShadow(bottom, top - bottom, 0);
-  if (curr_thread->has_fake_stack())
+  if (curr_thread && curr_thread->has_fake_stack())
     curr_thread->fake_stack()->HandleNoReturn();
 }
 
Index: compiler-rt/trunk/test/asan/TestCases/Windows/dll_control_c.cc
===================================================================
--- compiler-rt/trunk/test/asan/TestCases/Windows/dll_control_c.cc
+++ compiler-rt/trunk/test/asan/TestCases/Windows/dll_control_c.cc
@@ -0,0 +1,130 @@
+// RUN: %clang_cl_asan -O0 %p/dll_host.cc -Fe%t
+// RUN: %clang_cl_asan -LD -O2 %s -Fe%t.dll
+// RUN: %run %t %t.dll 2>&1 | FileCheck %s
+
+// Check that ASan does not CHECK fail when SEH is used around a crash from a
+// thread injected by control C.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <windows.h>
+
+static void __declspec(noinline) CrashOnProcessDetach() {
+  printf("CrashOnProcessDetach\n");
+  fflush(stdout);
+  *static_cast<volatile int *>(0) = 0x356;
+}
+
+bool g_is_child = false;
+
+BOOL WINAPI DllMain(PVOID h, DWORD reason, PVOID reserved) {
+  if (reason == DLL_PROCESS_DETACH && g_is_child) {
+    printf("in DllMain DLL_PROCESS_DETACH\n");
+    fflush(stdout);
+    __try {
+      CrashOnProcessDetach();
+    } __except (1) {
+      printf("caught crash\n");
+      fflush(stdout);
+    }
+  }
+  return true;
+}
+
+static void run_child() {
+  // Send this process group Ctrl+C. That should only be this process.
+  printf("GenerateConsoleCtrlEvent\n");
+  fflush(stdout);
+  GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0);
+  Sleep(10 * 1000); // Wait 10 seconds, and the process should die.
+  printf("unexpected execution after interrupt\n");
+  fflush(stdout);
+  exit(0x42);
+}
+
+static int WINAPI ignore_control_c(DWORD ctrl_type) {
+  // Don't interrupt the parent.
+  return ctrl_type == CTRL_C_EVENT;
+}
+
+static int run_parent() {
+  // Set an environment variable to tell the child process to interrupt itself.
+  if (!SetEnvironmentVariableW(L"DO_CONTROL_C", L"1")) {
+    printf("SetEnvironmentVariableW failed (0x%8lx).\n", GetLastError());
+    fflush(stdout);
+    return 2;
+  }
+
+  // Launch a new process using the current executable with a new console.
+  // Ctrl-C events are console-wide, so we need a new console.
+  STARTUPINFOW si;
+  memset(&si, 0, sizeof(si));
+  si.cb = sizeof(si);
+  // Hides the new console window that we are creating.
+  si.dwFlags |= STARTF_USESHOWWINDOW;
+  si.wShowWindow = SW_HIDE;
+  // Ensures that stdout still goes to the parent despite the new console.
+  si.dwFlags |= STARTF_USESTDHANDLES;
+  si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
+  si.hStdOutput = GetStdHandle(STD_OUTPUT_HANDLE);
+  si.hStdError = GetStdHandle(STD_ERROR_HANDLE);
+
+  PROCESS_INFORMATION pi;
+  memset(&pi, 0, sizeof(pi));
+  int flags = CREATE_NO_WINDOW | CREATE_NEW_PROCESS_GROUP | CREATE_NEW_CONSOLE;
+  if (!CreateProcessW(nullptr,           // No module name (use command line)
+                      GetCommandLineW(), // Command line
+                      nullptr,           // Process handle not inheritable
+                      nullptr,           // Thread handle not inheritable
+                      TRUE,              // Set handle inheritance to TRUE
+                      flags,             // Flags to give the child a console
+                      nullptr,           // Use parent's environment block
+                      nullptr,           // Use parent's starting directory
+                      &si, &pi)) {
+    printf("CreateProcess failed (0x%08lx).\n", GetLastError());
+    fflush(stdout);
+    return 2;
+  }
+
+  // Wait until child process exits.
+  if (WaitForSingleObject(pi.hProcess, INFINITE) == WAIT_FAILED) {
+    printf("WaitForSingleObject failed (0x%08lx).\n", GetLastError());
+    fflush(stdout);
+    return 2;
+  }
+
+  // Get the exit code. It should be the one for ctrl-c events.
+  DWORD rc;
+  if (!GetExitCodeProcess(pi.hProcess, &rc)) {
+    printf("GetExitCodeProcess failed (0x%08lx).\n", GetLastError());
+    fflush(stdout);
+    return 2;
+  }
+  if (rc == STATUS_CONTROL_C_EXIT)
+    printf("child quit with STATUS_CONTROL_C_EXIT\n");
+  else
+    printf("unexpected exit code: 0x%08lx\n", rc);
+  fflush(stdout);
+
+  // Close process and thread handles.
+  CloseHandle(pi.hProcess);
+  CloseHandle(pi.hThread);
+  return 0;
+}
+
+// CHECK: in DllMain DLL_PROCESS_DETACH
+// CHECK: CrashOnProcessDetach
+// CHECK: caught crash
+// CHECK: child quit with STATUS_CONTROL_C_EXIT
+
+extern "C" int __declspec(dllexport) test_function() {
+  wchar_t buf[260];
+  int len = GetEnvironmentVariableW(L"DO_CONTROL_C", buf, 260);
+  if (len > 0) {
+    g_is_child = true;
+    run_child();
+  } else {
+    exit(run_parent());
+  }
+  return 0;
+}