Merge pull request #73 from dscho/try-to-fix-hangs-on-arm64

Fix double-fork hang on Windows/ARM64

Author: dscho

winsup/cygwin/cygthread.cc

@@ -302,6 +302,20 @@ cygthread::terminate_thread ()
   if (!inuse)
     goto force_notterminated;
 
+  if (_my_tls._ctinfo != this)
+    {
+      CONTEXT context;
+      context.ContextFlags = CONTEXT_CONTROL;
+      /* SuspendThread makes sure a thread is "booted" from emulation before
+	 it is suspended.  As such, the emulator hopefully won't be in a bad
+	 state (aka, holding any locks) when the thread is terminated. */
+      SuspendThread (h);
+      /* We need to call GetThreadContext, even though we don't care about the
+	 context, because SuspendThread is asynchronous and GetThreadContext
+	 will make sure the thread is *really* suspended before returning */
+      GetThreadContext (h, &context);
+    }
+
   TerminateThread (h, 0);
   WaitForSingleObject (h, INFINITE);
   CloseHandle (h);

winsup/cygwin/pinfo.cc

@@ -1262,13 +1262,14 @@ proc_waiter (void *arg)
 
   for (;;)
     {
-      DWORD nb;
+      DWORD nb, err;
       char buf = '\0';
 
       if (!ReadFile (vchild.rd_proc_pipe, &buf, 1, &nb, NULL)
-	  && GetLastError () != ERROR_BROKEN_PIPE)
+	  && (err = GetLastError ()) != ERROR_BROKEN_PIPE)
 	{
-	  system_printf ("error on read of child wait pipe %p, %E", vchild.rd_proc_pipe);
+	  if (err != ERROR_OPERATION_ABORTED)
+	    system_printf ("error on read of child wait pipe %p, %E", vchild.rd_proc_pipe);
 	  break;
 	}
 

winsup/cygwin/sigproc.cc

@@ -410,7 +410,8 @@ proc_terminate ()
 	  if (!have_execed || !have_execed_cygwin)
 	    chld_procs[i]->ppid = 1;
 	  if (chld_procs[i].wait_thread)
-	    chld_procs[i].wait_thread->terminate_thread ();
+	    if (!CancelSynchronousIo (chld_procs[i].wait_thread->thread_handle ()))
+	      chld_procs[i].wait_thread->terminate_thread ();
 	  /* Release memory associated with this process unless it is 'myself'.
 	     'myself' is only in the chld_procs table when we've execed.  We
 	     reach here when the next process has finished initializing but we