On Thu, Mar 05, 2026 at 09:10:00PM +0000, Aleksei Oladko wrote:
> Several forwarding tests (e.g., gre_multipath.sh) initialize both IPv4
> and IPv6 addresses using simple_if_init, but only clean up IPv4
> in simple_if_fini. This leaves stale IPv6 addresses on the interfaces,
> which causes subsequent tests to fail when they encounter unexpected
> address configuration.
>
> The issue can be reproduced by running tests in sequence:
> # run_kselftest.sh -t net/forwarding:ipip_hier_gre.sh
> # run_kselftest.sh -t net/forwarding:min_max_mtu.sh
> TAP version 13
> 1..1
> # timeout set to 0
> # selftests: net/forwarding: min_max_mtu.sh
> # TEST: ping [ OK ]
> # TEST: ping6 [ OK ]
> # TEST: Test maximum MTU configuration [ OK ]
> # TEST: Test traffic, packet size is maximum MTU [FAIL]
> # Ping6, packet size: 65487 succeeded, but should have failed
> # TEST: Test minimum MTU configuration [ OK ]
> # TEST: Test traffic, packet size is minimum MTU [ OK ]
> not ok 1 selftests: net/forwarding: min_max_mtu.sh # exit=1
>
> Fix this by removing the unused IPv6 argument from simple_if_init in
> tests that don't use IPv6 (gre_multipath.sh, ipip_lib.sh), and by
> adding the missing IPv6 argument to simple_if_fini in tests that
> use IPv6 (gre_multipath_nh.sh, gre_multipath_nh_res.sh).
>
> Fixes: fed926d4f64c ("selftests: forwarding: Add IP tunneling lib")
> Fixes: 902280cacc03 ("selftests: forwarding: Add resilient multipath
> tunneling nexthop test")
> Fixes: 54818c4c4b93 ("selftests: forwarding: Test multipath tunneling")
> Fixes: e035146d6560 ("selftests: forwarding: Add multipath tunneling nexthop
> test")
> Signed-off-by: Aleksei Oladko <[email protected]>
Reviewed-by: Ido Schimmel <[email protected]>
