an issue where an IPv6 route between namespaced interfaces does not get deleted. testcase : #!/bin/sh set -x ip netns add fib_1 ip netns add fib_2 ip link set eth10 netns fib_1 ip link set eth11 netns fib_2 ip netns exec fib_1 ifconfig eth10 10.1.2.1/24 up ip netns exec fib_2 ifconfig eth11 10.1.1.1/24 up ip netns exec fib_1 ip -6 addr add 2001:1b70:82a8:14:1080:8:0:2/128 dev eth10 ip netns exec fib_2 ip -6 addr add 2001:1b70:82a8:14:80:8:0:2/128 dev eth11 ip netns exec fib_1 ifconfig eth10 up ip netns exec fib_2 ifconfig eth11 up ip link add vr1-2 type veth peer name vr2-1 ip link set vr1-2 netns fib_1 ip link set vr2-1 netns fib_2 ip netns exec fib_1 sysctl -w net.ipv6.conf.vr1-2.disable_ipv6=0 ip netns exec fib_2 sysctl -w net.ipv6.conf.vr2-1.disable_ipv6=0 ip netns exec fib_1 ifconfig vr1-2 -arp ip netns exec fib_2 ifconfig vr2-1 -arp ip netns exec fib_1 ifconfig vr1-2 hw ether 00:0c:00:00:00:00 ip netns exec fib_2 ifconfig vr2-1 hw ether 00:0c:00:00:00:00 ip netns exec fib_1 ip link set vr1-2 up ip netns exec fib_2 ip link set vr2-1 up ip netns exec fib_1 ip route add 10.1.1.1 dev vr1-2 ip netns exec fib_2 ip route add 10.1.2.1 dev vr2-1 ip netns exec fib_1 ip route add 2001:1b70:82a8:14:80:8:0:2/128 dev vr1-2 ip netns exec fib_2 ip route add 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 ip netns exec fib_2 ping6 -c 5 2001:1b70:82a8:14:1080:8:0:2 ip netns exec fib_2 ip -6 route show ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 # This delete succeeds, but the route is still there ip netns exec fib_2 ip -6 route show ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 ip netns exec fib_2 ip -6 route show Script output on kernel 4.1.21-rt13-wrl800.20_1.78_3: + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 pref medium 2001:1b70:82a8:14:1080:8:0:2 dev vr2-1 metric 1024 pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 pref medium ff00::/8 dev vr2-1 metric 256 pref medium + ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 pref medium 2001:1b70:82a8:14:1080:8:0:2 dev vr2-1 metric 1024 pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 pref medium ff00::/8 dev vr2-1 metric 256 pref medium + ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 pref medium ff00::/8 dev vr2-1 metric 256 pref medium Same script works on WRL18 — output on kernel 4.18.45-rt8-wrl18.13_1.22_545: + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 linkdown pref medium 2001:1b70:82a8:14:1080:8:0:2 dev vr2-1 metric 1024 pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 linkdown pref medium ff00::/8 dev vr2-1 metric 256 pref medium + ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 linkdown pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 linkdown pref medium ff00::/8 dev vr2-1 metric 256 pref medium + ip netns exec fib_2 ip route del 2001:1b70:82a8:14:1080:8:0:2/128 dev vr2-1 RTNETLINK answers: No such process + ip netns exec fib_2 ip -6 route show 2001:1b70:82a8:14:80:8:0:2 dev eth11 proto kernel metric 256 linkdown pref medium fe80::/64 dev vr2-1 proto kernel metric 256 pref medium ff00::/8 dev eth11 metric 256 linkdown pref medium ff00::/8 dev vr2-1 metric 256 pref medium
