VM: Avoid running atexit() handlers during exit() of a failed subprocess spawn

runtime/bin/process_linux.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #if !defined(DART_IO_DISABLED)
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_LINUX)
 
 #include "bin/process.h"
@@ skipping 664 matching lines @@
     const int kBufferSize = 1024;
     char error_buf[kBufferSize];
     char* os_error_message = Utils::StrError(errno, error_buf, kBufferSize);
     int bytes_written = FDUtils::WriteToBlocking(exec_control_[1], &child_errno,
                                                  sizeof(child_errno));
     if (bytes_written == sizeof(child_errno)) {
       FDUtils::WriteToBlocking(exec_control_[1], os_error_message,
                                strlen(os_error_message) + 1);
     }
     VOID_TEMP_FAILURE_RETRY(close(exec_control_[1]));
-    exit(1);
+
+    // We avoid running through registered atexit() handlers because that is
+    // unnecessary work.
+    _exit(1);
   }
 
 
   void ReportPid(int pid) {
     // In the case of starting a detached process the actual pid of that process
     // is communicated using the exec control pipe.
     int bytes_written =
         FDUtils::WriteToBlocking(exec_control_[1], &pid, sizeof(pid));
     ASSERT(bytes_written == sizeof(int));
     USE(bytes_written);
@@ skipping 294 matching lines @@
     sigaction(signal, &act, NULL);
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)
 
 #endif  // !defined(DART_IO_DISABLED)