From: Jiayuan Chen <[email protected]> Add a selftest to verify that changing xmit_hash_policy to vlan+srcmac is rejected when a native XDP program is loaded on a bond in 802.3ad mode. Without the fix in bond_option_xmit_hash_policy_set(), the change succeeds silently, creating an inconsistent state that triggers a kernel WARNING in dev_xdp_uninstall() when the bond is torn down.
The test attaches native XDP to a bond0 (802.3ad, layer2+3), then attempts to switch xmit_hash_policy to vlan+srcmac and asserts the operation fails. It also verifies the change succeeds after XDP is detached, confirming the rejection is specific to the XDP-loaded state. Signed-off-by: Jiayuan Chen <[email protected]> --- .../selftests/bpf/prog_tests/xdp_bonding.c | 58 +++++++++++++++++++ 1 file changed, 58 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c index a5b15e464018..0d4ec1e5b401 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_bonding.c @@ -704,6 +704,61 @@ static void test_xdp_bonding_features(struct skeletons *skeletons) system("ip link del bond"); } +/* + * Test that changing xmit_hash_policy to vlan+srcmac is rejected when a + * native XDP program is loaded on a bond in 802.3ad or balance-xor mode. + * These modes support XDP only when xmit_hash_policy != vlan+srcmac; freely + * changing the policy creates an inconsistency that triggers a WARNING in + * dev_xdp_uninstall() during device teardown. + */ +static void test_xdp_bonding_xmit_policy_compat(struct skeletons *skeletons) +{ + struct nstoken *nstoken = NULL; + int bond_ifindex = -1; + int xdp_fd, err; + + SYS(out, "ip netns add ns_xmit_policy"); + nstoken = open_netns("ns_xmit_policy"); + if (!ASSERT_OK_PTR(nstoken, "open ns_xmit_policy")) + goto out; + + /* 802.3ad with layer2+3 policy: native XDP is supported */ + SYS(out, "ip link add bond0 type bond mode 802.3ad xmit_hash_policy layer2+3"); + SYS(out, "ip link add veth0 type veth peer name veth0p"); + SYS(out, "ip link set veth0 master bond0"); + SYS(out, "ip link set bond0 up"); + + bond_ifindex = if_nametoindex("bond0"); + if (!ASSERT_GT(bond_ifindex, 0, "bond0 ifindex")) + goto out; + + xdp_fd = bpf_program__fd(skeletons->xdp_dummy->progs.xdp_dummy_prog); + if (!ASSERT_GE(xdp_fd, 0, "xdp_dummy fd")) + goto out; + + err = bpf_xdp_attach(bond_ifindex, xdp_fd, XDP_FLAGS_DRV_MODE, NULL); + if (!ASSERT_OK(err, "attach XDP to bond0")) + goto out; + + /* With XDP loaded, switching to vlan+srcmac must be rejected */ + err = system("ip link set bond0 type bond xmit_hash_policy vlan+srcmac 2>/dev/null"); + ASSERT_NEQ(err, 0, "vlan+srcmac change with XDP loaded should fail"); + + /* Detach XDP first, then the same change must succeed */ + ASSERT_OK(bpf_xdp_detach(bond_ifindex, XDP_FLAGS_DRV_MODE, NULL), + "detach XDP from bond0"); + + bond_ifindex = -1; + err = system("ip link set bond0 type bond xmit_hash_policy vlan+srcmac 2>/dev/null"); + ASSERT_OK(err, "vlan+srcmac change without XDP should succeed"); + +out: + if (bond_ifindex > 0) + bpf_xdp_detach(bond_ifindex, XDP_FLAGS_DRV_MODE, NULL); + close_netns(nstoken); + SYS_NOFAIL("ip netns del ns_xmit_policy"); +} + static int libbpf_debug_print(enum libbpf_print_level level, const char *format, va_list args) { @@ -771,6 +826,9 @@ void serial_test_xdp_bonding(void) test_case->xmit_policy); } + if (test__start_subtest("xdp_bonding_xmit_policy_compat")) + test_xdp_bonding_xmit_policy_compat(&skeletons); + if (test__start_subtest("xdp_bonding_redirect_multi")) test_xdp_bonding_redirect_multi(&skeletons); -- 2.43.0
