selftests: pmtu: fix and increase coverage

index e2c94e47707c..89aec2fdf4fa 100755
@@ -263,8 +263,6 @@ setup_fou_or_gue() {
 
 	${ns_a} ip link set ${encap}_a up
 	${ns_b} ip link set ${encap}_b up
-
-	sleep 1
 }
 
 setup_fou44() {

@@ -302,6 +300,10 @@ setup_gue66() {
 setup_namespaces() {
 	for n in ${NS_A} ${NS_B} ${NS_R1} ${NS_R2}; do
 		ip netns add ${n} || return 1
+
+		# Disable DAD, so that we don't have to wait to use the
+		# configured IPv6 addresses
+		ip netns exec ${n} sysctl -q net/ipv6/conf/default/accept_dad=0
 	done
 }
 

@@ -337,8 +339,6 @@ setup_vti() {
 
 	${ns_a} ip link set vti${proto}_a up
 	${ns_b} ip link set vti${proto}_b up
-
-	sleep 1
 }
 
 setup_vti4() {

@@ -375,8 +375,6 @@ setup_vxlan_or_geneve() {
 
 	${ns_a} ip link set ${type}_a up
 	${ns_b} ip link set ${type}_b up
-
-	sleep 1
 }
 
 setup_geneve4() {

@@ -588,8 +586,8 @@ test_pmtu_ipvX() {
 	mtu "${ns_b}"  veth_B-R2 1500
 
 	# Create route exceptions
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1800 ${dst1} > /dev/null
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1800 ${dst2} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1800 ${dst1} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1800 ${dst2} > /dev/null
 
 	# Check that exceptions have been created with the correct PMTU
 	pmtu_1="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst1})"

@@ -621,7 +619,7 @@ test_pmtu_ipvX() {
 	# Decrease remote MTU on path via R2, get new exception
 	mtu "${ns_r2}" veth_R2-B 400
 	mtu "${ns_b}"  veth_B-R2 400
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1400 ${dst2} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1400 ${dst2} > /dev/null
 	pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})"
 	check_pmtu_value "lock 552" "${pmtu_2}" "exceeding MTU, with MTU < min_pmtu" || return 1
 

@@ -638,7 +636,7 @@ test_pmtu_ipvX() {
 	check_pmtu_value "1500" "${pmtu_2}" "increasing local MTU" || return 1
 
 	# Get new exception
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s 1400 ${dst2} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s 1400 ${dst2} > /dev/null
 	pmtu_2="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst2})"
 	check_pmtu_value "lock 552" "${pmtu_2}" "exceeding MTU, with MTU < min_pmtu" || return 1
 }

@@ -687,7 +685,7 @@ test_pmtu_ipvX_over_vxlanY_or_geneveY_exception() {
 
 	mtu "${ns_a}" ${type}_a $((${ll_mtu} + 1000))
 	mtu "${ns_b}" ${type}_b $((${ll_mtu} + 1000))
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s $((${ll_mtu} + 500)) ${dst} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s $((${ll_mtu} + 500)) ${dst} > /dev/null
 
 	# Check that exception was created
 	pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst})"

@@ -767,7 +765,7 @@ test_pmtu_ipvX_over_fouY_or_gueY() {
 
 	mtu "${ns_a}" ${encap}_a $((${ll_mtu} + 1000))
 	mtu "${ns_b}" ${encap}_b $((${ll_mtu} + 1000))
-	${ns_a} ${ping} -q -M want -i 0.1 -w 2 -s $((${ll_mtu} + 500)) ${dst} > /dev/null
+	${ns_a} ${ping} -q -M want -i 0.1 -w 1 -s $((${ll_mtu} + 500)) ${dst} > /dev/null
 
 	# Check that exception was created
 	pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${dst})"

@@ -825,13 +823,13 @@ test_pmtu_vti4_exception() {
 
 	# Send DF packet without exceeding link layer MTU, check that no
 	# exception is created
-	${ns_a} ping -q -M want -i 0.1 -w 2 -s ${ping_payload} ${tunnel4_b_addr} > /dev/null
+	${ns_a} ping -q -M want -i 0.1 -w 1 -s ${ping_payload} ${tunnel4_b_addr} > /dev/null
 	pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
 	check_pmtu_value "" "${pmtu}" "sending packet smaller than PMTU (IP payload length ${esp_payload_rfc4106})" || return 1
 
 	# Now exceed link layer MTU by one byte, check that exception is created
 	# with the right PMTU value
-	${ns_a} ping -q -M want -i 0.1 -w 2 -s $((ping_payload + 1)) ${tunnel4_b_addr} > /dev/null
+	${ns_a} ping -q -M want -i 0.1 -w 1 -s $((ping_payload + 1)) ${tunnel4_b_addr} > /dev/null
 	pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel4_b_addr})"
 	check_pmtu_value "${esp_payload_rfc4106}" "${pmtu}" "exceeding PMTU (IP payload length $((esp_payload_rfc4106 + 1)))"
 }

@@ -847,7 +845,7 @@ test_pmtu_vti6_exception() {
 	mtu "${ns_b}" veth_b 4000
 	mtu "${ns_a}" vti6_a 5000
 	mtu "${ns_b}" vti6_b 5000
-	${ns_a} ${ping6} -q -i 0.1 -w 2 -s 60000 ${tunnel6_b_addr} > /dev/null
+	${ns_a} ${ping6} -q -i 0.1 -w 1 -s 60000 ${tunnel6_b_addr} > /dev/null
 
 	# Check that exception was created
 	pmtu="$(route_get_dst_pmtu_from_exception "${ns_a}" ${tunnel6_b_addr})"

index 89aec2fdf4fa..912b2dc50be3 100755
@@ -103,6 +103,15 @@
 #	and check that configured MTU is used on link creation and changes, and
 #	that MTU is properly calculated instead when MTU is not configured from
 #	userspace
+#
+# - cleanup_ipv4_exception
+#	Similar to pmtu_ipv4_vxlan4_exception, but explicitly generate PMTU
+#	exceptions on multiple CPUs and check that the veth device tear-down
+# 	happens in a timely manner
+#
+# - cleanup_ipv6_exception
+#	Same as above, but use IPv6 transport from A to B
+
 
 # Kselftest framework requirement - SKIP code is 4.
 ksft_skip=4

@@ -135,7 +144,9 @@ tests="
 	pmtu_vti6_default_mtu		vti6: default MTU assignment
 	pmtu_vti4_link_add_mtu		vti4: MTU setting on link creation
 	pmtu_vti6_link_add_mtu		vti6: MTU setting on link creation
-	pmtu_vti6_link_change_mtu	vti6: MTU changes on link changes"
+	pmtu_vti6_link_change_mtu	vti6: MTU changes on link changes
+	cleanup_ipv4_exception		ipv4: cleanup of cached exceptions
+	cleanup_ipv6_exception		ipv6: cleanup of cached exceptions"
 
 NS_A="ns-$(mktemp -u XXXXXX)"
 NS_B="ns-$(mktemp -u XXXXXX)"

@@ -1006,6 +1017,61 @@ test_pmtu_vti6_link_change_mtu() {
 	return ${fail}
 }
 
+check_command() {
+	cmd=${1}
+
+	if ! which ${cmd} > /dev/null 2>&1; then
+		err "  missing required command: '${cmd}'"
+		return 1
+	fi
+	return 0
+}
+
+test_cleanup_vxlanX_exception() {
+	outer="${1}"
+	encap="vxlan"
+	ll_mtu=4000
+
+	check_command taskset || return 2
+	cpu_list=$(grep -m 2 processor /proc/cpuinfo | cut -d ' ' -f 2)
+
+	setup namespaces routing ${encap}${outer} || return 2
+	trace "${ns_a}" ${encap}_a   "${ns_b}"  ${encap}_b \
+	      "${ns_a}" veth_A-R1    "${ns_r1}" veth_R1-A \
+	      "${ns_b}" veth_B-R1    "${ns_r1}" veth_R1-B
+
+	# Create route exception by exceeding link layer MTU
+	mtu "${ns_a}"  veth_A-R1 $((${ll_mtu} + 1000))
+	mtu "${ns_r1}" veth_R1-A $((${ll_mtu} + 1000))
+	mtu "${ns_b}"  veth_B-R1 ${ll_mtu}
+	mtu "${ns_r1}" veth_R1-B ${ll_mtu}
+
+	mtu "${ns_a}" ${encap}_a $((${ll_mtu} + 1000))
+	mtu "${ns_b}" ${encap}_b $((${ll_mtu} + 1000))
+
+	# Fill exception cache for multiple CPUs (2)
+	# we can always use inner IPv4 for that
+	for cpu in ${cpu_list}; do
+		taskset --cpu-list ${cpu} ${ns_a} ping -q -M want -i 0.1 -w 1 -s $((${ll_mtu} + 500)) ${tunnel4_b_addr} > /dev/null
+	done
+
+	${ns_a} ip link del dev veth_A-R1 &
+	iplink_pid=$!
+	sleep 1
+	if [ "$(cat /proc/${iplink_pid}/cmdline 2>/dev/null | tr -d '\0')" = "iplinkdeldevveth_A-R1" ]; then
+		err "  can't delete veth device in a timely manner, PMTU dst likely leaked"
+		return 1
+	fi
+}
+
+test_cleanup_ipv6_exception() {
+	test_cleanup_vxlanX_exception 6
+}
+
+test_cleanup_ipv4_exception() {
+	test_cleanup_vxlanX_exception 4
+}
+
 usage() {
 	echo
 	echo "$0 [OPTIONS] [TEST]..."