diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index af2230ce9..299caf708 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2011-06-03  Christopher Faylor  <me.cygwin2011@cgf.cx>
+
+	* pinfo.cc (_pinfo::set_ctty): Don't reset myself->{pgid,sid} if
+	terminal has no pgid or sid settings.
+
 2011-06-03  Christopher Faylor  <me.cygwin2011@cgf.cx>
 
 	* fhandler.cc (fhandler_base_overlapped::wait_overlapped): Only raise
diff --git a/winsup/cygwin/pinfo.cc b/winsup/cygwin/pinfo.cc
index c81786359..8a1780c82 100644
--- a/winsup/cygwin/pinfo.cc
+++ b/winsup/cygwin/pinfo.cc
@@ -404,7 +404,7 @@ _pinfo::set_ctty (tty_min *tc, int flags, fhandler_termios *fh)
       syscall_printf ("attaching %s sid %d, pid %d, pgid %d, tty->pgid %d, tty->sid %d",
 		      __ctty (), sid, pid, pgid, tc->getpgid (), tc->getsid ());
       if (!cygwin_finished_initializing && !myself->cygstarted
-	  && myself->pgid == myself->pid)
+	  && myself->pgid == myself->pid && tc->getpgid () && tc->getsid ())
 	{
 	  myself->pgid = tc->getpgid ();
 	  myself->sid = tc->getsid ();