diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index b81454497..1fe10ec45 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2011-11-28  Corinna Vinschen  <vinschen@redhat.com>
+
+	* external.cc (fillout_pinfo): Store program name as POSIX path in
+	ep.progname_long.
+
 2011-11-28  Corinna Vinschen  <vinschen@redhat.com>
 
 	* pinfo.cc (pinfo::exit): Call TerminateProcess to avoid potential
diff --git a/winsup/cygwin/external.cc b/winsup/cygwin/external.cc
index 35f0f0909..58639fe63 100644
--- a/winsup/cygwin/external.cc
+++ b/winsup/cygwin/external.cc
@@ -99,7 +99,7 @@ fillout_pinfo (pid_t pid, int winpid)
 	  ep.gid32 = p->gid;
 
 	  ep.progname_long = ep_progname_long_buf;
-	  sys_wcstombs(ep.progname_long, NT_MAX_PATH, p->progname);
+	  mount_table->conv_to_posix_path (p->progname, ep.progname_long, 0);
 	  break;
 	}
     }