* sync.h (sync::init_lock): Declare new static member.

(sync::init()): Declare new static function.
* sync.cc (sync::init): Define.
(sync::init): Lock attempt to initialize a muto to stop multiple threads from
colliding.
* dcrt0.cc (dll_crt0_0): Initialize muto environment.

winsup/cygwin/dcrt0.cc

@@ -574,6 +574,7 @@ void __stdcall
 dll_crt0_0 ()
 {
   wincap.init ();
+  muto::init ();
   initial_env ();
 
   char zeros[sizeof (child_proc_info->zero)] = {0};

winsup/cygwin/sync.cc

@@ -28,6 +28,13 @@ details. */
 #undef WaitForSingleObject
 
 DWORD NO_COPY muto::exiting_thread;
+CRITICAL_SECTION NO_COPY muto::init_lock;
+
+void
+muto::init ()
+{
+  InitializeCriticalSection (&init_lock);
+}
 
 void
 muto::grab ()
@@ -39,15 +46,23 @@ muto::grab ()
 muto *
 muto::init (const char *s)
 {
-  waiters = -1;
-  /* Create event which is used in the fallback case when blocking is necessary */
-  if (!(bruteforce = CreateEvent (&sec_none_nih, FALSE, FALSE, NULL)))
+  muto *res = this;
+  EnterCriticalSection (&init_lock);
+  if (!bruteforce)
     {
-      DWORD oerr = GetLastError ();
-      SetLastError (oerr);
-      return NULL;
+      waiters = -1;
+      bruteforce = CreateEvent (&sec_none_nih, FALSE, FALSE, NULL);
+      /* Create event which is used in the fallback case when blocking is necessary */
+      if (bruteforce)
+	name = s;
+      else
+	{
+	  DWORD oerr = GetLastError ();
+	  SetLastError (oerr);
+	  res = NULL;
+	}
     }
-  name = s;
+  LeaveCriticalSection (&init_lock);
   return this;
 }
 

winsup/cygwin/sync.h

@@ -17,6 +17,7 @@ details. */
 class muto
 {
   static DWORD exiting_thread;
+  static CRITICAL_SECTION init_lock;
   LONG sync;	/* Used to serialize access to this class. */
   LONG waiters;	/* Number of threads waiting for lock. */
   HANDLE bruteforce; /* event handle used to control waiting for lock. */
@@ -39,6 +40,7 @@ public:
   void upforgrabs () {tls = this;}  // just set to an invalid address
   void grab () __attribute__ ((regparm (1)));
   static void set_exiting_thread () {exiting_thread = GetCurrentThreadId ();}
+  static void init ();
 };
 
 extern muto muto_start;