diff --git a/usr.bin/make/unit-tests/export-all b/usr.bin/make/unit-tests/export-all
index 05429379e0fc..d1c79e2d341e 100644
--- a/usr.bin/make/unit-tests/export-all
+++ b/usr.bin/make/unit-tests/export-all
@@ -1,8 +1,20 @@
-# $Id: export-all,v 1.1 2007/10/05 15:27:46 sjg Exp $
+# $Id: export-all,v 1.2 2010/04/21 04:25:28 sjg Exp $
 
 UT_OK=good
 UT_F=fine
 
+# the old way to do :tA
+M_tAbad = C,.*,cd & \&\& 'pwd',:sh
+# the new
+M_tA = tA
+
+here := ${.PARSEDIR}
+
+# this will cause trouble (recursing if we let it)
+UT_BADDIR = ${${here}/../${here:T}:L:${M_tAbad}:T}
+# this will be ok
+UT_OKDIR = ${${here}/../${here:T}:L:${M_tA}:T}
+
 .export
 
 .include "export"
diff --git a/usr.bin/make/unit-tests/test.exp b/usr.bin/make/unit-tests/test.exp
index 660e28982ca7..c13e852d30b6 100644
--- a/usr.bin/make/unit-tests/test.exp
+++ b/usr.bin/make/unit-tests/test.exp
@@ -33,12 +33,14 @@ UT_FU=fubar
 UT_TEST=export
 UT_ZOO=hoopie
 UT_ALL=even this gets exported
+UT_BADDIR=unit-tests
 UT_DOLLAR=This is $UT_FU
 UT_F=fine
 UT_FOO=foobar is fubar
 UT_FU=fubar
 UT_NO=all
 UT_OK=good
+UT_OKDIR=unit-tests
 UT_TEST=export-all
 UT_ZOO=hoopie
 At first, I am
diff --git a/usr.bin/make/var.c b/usr.bin/make/var.c
index c2b2e3038459..770e688f5c28 100644
--- a/usr.bin/make/var.c
+++ b/usr.bin/make/var.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: var.c,v 1.157 2010/04/20 17:48:16 sjg Exp $	*/
+/*	$NetBSD: var.c,v 1.158 2010/04/21 04:25:27 sjg Exp $	*/
 
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
@@ -69,14 +69,14 @@
  */
 
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: var.c,v 1.157 2010/04/20 17:48:16 sjg Exp $";
+static char rcsid[] = "$NetBSD: var.c,v 1.158 2010/04/21 04:25:27 sjg Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: var.c,v 1.157 2010/04/20 17:48:16 sjg Exp $");
+__RCSID("$NetBSD: var.c,v 1.158 2010/04/21 04:25:27 sjg Exp $");
 #endif
 #endif /* not lint */
 #endif
@@ -591,6 +591,13 @@ Var_Export1(const char *name, int parent)
 	    v->flags |= (VAR_EXPORTED|VAR_REEXPORT);
 	    return 1;
 	}
+	if (v->flags & VAR_IN_USE) {
+	    /*
+	     * We recursed while exporting in a child.
+	     * This isn't going to end well, just skip it.
+	     */
+	    return 0;
+	}
 	n = snprintf(tmp, sizeof(tmp), "${%s}", name);
 	if (n < (int)sizeof(tmp)) {
 	    val = Var_Subst(NULL, tmp, VAR_GLOBAL, 0);