Revert "ipv6: preserve insertion order for same-scope addresses"

Chris Adams reported that preserving insertion order for same-scope
addresses is causing SSH connections to be dropped after stopping a VM
while running NetworkManager.

NetworkManager caches the IPv6 address configuration, when a RA arrives,
it determines the list of addresses to configure and checks if the
addresses are already in the right order in the kernel. If they aren't,
NetworkManager removes and re-adds them to achieve the desired order.

As the order changes, NetworkManager is confused and reconfigures the
addresses on every update. In addition, this would also affect to cloud
tooling that relies on IPv6 addresses order to identify primary and
secondaries addresses.

This reverts commit cb3de96eea66f5e4a580086c6a1be46e765f97f4.

Fixes: cb3de96eea66 ("ipv6: preserve insertion order for same-scope addresses")
Reported-by: Chris Adams <linux@cmadams.net>
Closes: https://lore.kernel.org/netdev/20260521135310.GC977@cmadams.net/
Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
Link: https://patch.msgid.link/20260529112357.5079-1-fmancera@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 5476b6536eb76f8e943684dbf2241bfbf0b32797..bb84a78b80f6e101b142253349842fb1a3966aa7 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1013,7 +1013,7 @@ ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
        list_for_each(p, &idev->addr_list) {
                struct inet6_ifaddr *ifa
                        = list_entry(p, struct inet6_ifaddr, if_list);
-               if (ifp_scope > ipv6_addr_src_scope(&ifa->addr))
+               if (ifp_scope >= ipv6_addr_src_scope(&ifa->addr))
                        break;
        }
 

diff --git a/tools/testing/selftests/net/ioam6.sh b/tools/testing/selftests/net/ioam6.sh
index b2b99889942f75b090867f6dda2b195eb3f89e44..845c26dd01a9324e8a99e222afffa211d3637780 100755 (executable)
--- a/tools/testing/selftests/net/ioam6.sh
+++ b/tools/testing/selftests/net/ioam6.sh
@@ -273,8 +273,8 @@ setup()
   ip -netns $ioam_node_beta link set ioam-veth-betaR name veth1 &>/dev/null
   ip -netns $ioam_node_gamma link set ioam-veth-gamma name veth0 &>/dev/null
 
-  ip -netns $ioam_node_alpha addr add 2001:db8:1::2/64 dev veth0 &>/dev/null
   ip -netns $ioam_node_alpha addr add 2001:db8:1::50/64 dev veth0 &>/dev/null
+  ip -netns $ioam_node_alpha addr add 2001:db8:1::2/64 dev veth0 &>/dev/null
   ip -netns $ioam_node_alpha link set veth0 up &>/dev/null
   ip -netns $ioam_node_alpha link set lo up &>/dev/null
   ip -netns $ioam_node_alpha route add 2001:db8:2::/64 \