selftests: net: use slowwait to stabilize vrf_route_leaking test

JIRA: https://issues.redhat.com/browse/RHEL-84202
Upstream Status: net-next.git commit d83a580

commit d83a580
Author: Hangbin Liu <liuhangbin@gmail.com>
Date:   Tue Jun 17 10:50:59 2025 +0000

    selftests: net: use slowwait to stabilize vrf_route_leaking test

    The vrf_route_leaking test occasionally fails due to connectivity issues
    in our testing environment. A sample failure message shows that the ping
    check fails intermittently

      PING 2001:db8:16:2::2 (2001:db8:16:2::2) 56 data bytes

      --- 2001:db8:16:2::2 ping statistics ---
      1 packets transmitted, 0 received, 100% packet loss, time 0ms

      TEST: Basic IPv6 connectivity                                       [FAIL]

    This is likely due to insufficient wait time on slower machines. To address
    this, switch to using slowwait, which provides a longer and more reliable
    wait for setup completion.

    Before this change, the test failed 3 out of 10 times. After applying this
    fix, the test was run 30 times without any failure.

    Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
    Reviewed-by: Simon Horman <horms@kernel.org>
    Link: https://patch.msgid.link/20250617105101.433718-2-liuhangbin@gmail.com
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: Hangbin Liu <haliu@redhat.com>

Author: Hangbin Liu

tools/testing/selftests/net/vrf_route_leaking.sh

@@ -275,7 +275,7 @@ setup_sym()
 
 
 	# Wait for ip config to settle
-	sleep 2
+	slowwait 5 ip netns exec $h1 "${ping6}" -c1 -w1 ${H2_N2_IP6} >/dev/null 2>&1
 }
 
 setup_asym()
@@ -370,7 +370,7 @@ setup_asym()
 	ip -netns $r2 -6 addr add dev eth1 ${R2_N2_IP6}/64 nodad
 
 	# Wait for ip config to settle
-	sleep 2
+	slowwait 5 ip netns exec $h1 "${ping6}" -c1 -w1 ${H2_N2_IP6} >/dev/null 2>&1
 }
 
 check_connectivity()