Add test cases for PR kern/53546 and PR kern/55417. Both are skipped as

both reproduce panics.

distrib/sets/lists/tests/mi

@@ -1,4 +1,4 @@
-# $NetBSD: mi,v 1.848 2020/06/24 10:05:07 jruoho Exp $
+# $NetBSD: mi,v 1.849 2020/06/25 14:24:45 jruoho Exp $
 #
 # Note: don't delete entries from here - mark them as "obsolete" instead.
 #
@@ -3991,6 +3991,7 @@
 ./usr/tests/sbin/ifconfig/Kyuafile		tests-sbin-tests	compattestfile,atf,kyua
 ./usr/tests/sbin/ifconfig/t_nonexistent		tests-sbin-tests	compattestfile,atf
 ./usr/tests/sbin/ifconfig/t_repeated_scan	tests-sbin-tests	compattestfile,atf
+./usr/tests/sbin/ifconfig/t_tap			tests-sbin-tests	compattestfile,atf
 ./usr/tests/sbin/newfs				tests-sbin-tests	compattestfile,atf
 ./usr/tests/sbin/newfs/Atffile			tests-sbin-tests	compattestfile,atf
 ./usr/tests/sbin/newfs/Kyuafile			tests-sbin-tests	compattestfile,atf,kyua

tests/sbin/ifconfig/Makefile

@@ -1,9 +1,9 @@
-# $NetBSD: Makefile,v 1.2 2020/06/24 09:11:26 jruoho Exp $
+# $NetBSD: Makefile,v 1.3 2020/06/25 14:24:46 jruoho Exp $
 
 .include <bsd.own.mk>
 
 TESTSDIR=	${TESTSBASE}/sbin/ifconfig
 
-TESTS_SH=	t_nonexistent t_repeated_scan
+TESTS_SH=	t_nonexistent t_repeated_scan t_tap
 
 .include <bsd.test.mk>

tests/sbin/ifconfig/t_tap.sh

@@ -0,0 +1,101 @@
+# $NetBSD: t_tap.sh,v 1.1 2020/06/25 14:24:46 jruoho Exp $
+#
+# Copyright (c) 2020 The NetBSD Foundation, Inc.
+# All rights reserved.
+#
+# This code is derived from software contributed to The NetBSD Foundation
+# by Jukka Ruohonen.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+taps="/tmp/taps"
+
+atf_test_case manytaps cleanup
+manytaps_head() {
+	atf_set "require.user" "root"
+	atf_set "descr" "Test creating many, many tap(4)'s (PR kern/55417)"
+}
+
+manytaps_body() {
+
+	atf_skip "The test causes a panic (PR kern/55417)"
+	seq 65535 64000 > $taps
+
+	while read tap; do
+
+		ifconfig "tap$tap"
+
+		if [ $? -eq 0 ]; then
+			echo "Skipping existing tap$tap"
+			continue
+		fi
+
+		ifconfig "tap$tap" create
+		echo "Created $tap"
+
+	done < $taps
+}
+
+manytaps_cleanup() {
+
+	if [ -f $taps ]; then
+
+		while read tap; do
+
+			ifconfig "tap$tap"
+
+			if [ $? -eq 0 ]; then
+				ifconfig "tap$tap" destroy
+				echo "Destroyed tap$tap"
+			fi
+
+		done < $taps
+
+		rm $taps
+	fi
+}
+
+atf_test_case overflow cleanup
+overflow_head() {
+	atf_set "require.user" "root"
+	atf_set "descr" "Test creating a tap(4) with a " \
+		"negative device number (PR kern/53546)"
+}
+
+overflow_body() {
+	atf_skip "The test causes a panic (PR kern/53546)"
+	ifconfig tap65537 create
+}
+
+overflow_cleanup() {
+
+	ifconfig tap65537
+
+	if [ $? -eq 0 ]; then
+		ifconfig tap65537 destroy
+	fi
+}
+
+atf_init_test_cases() {
+	atf_add_test_case manytaps
+	atf_add_test_case overflow
+}