[PATCH net 6/7] selftests/xsk: fix too-many-frags multi-buffer Tx test
From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Date: 2026-06-23 13:33:32
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest, xdp sockets (af_xdp) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
The too-many-frags test describes a packet that is valid from the Tx ring ownership point of view, but invalid for transmission because it exceeds the supported number of fragments. Keep the generated Tx descriptors valid so that __send_pkts() accounts them as outstanding descriptors that must be reclaimed through the CQ. Then mark the corresponding Rx packet invalid so the test still does not expect the oversized packet to appear on the receive side. Add a valid synchronization packet after the oversized packet so the test can verify that the Tx path drains the bad packet and resumes at the next packet boundary. Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> --- .../selftests/bpf/prog_tests/test_xsk.c | 20 +++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.c b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
index 72875071d4f1..de1e63c3fdf6 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_xsk.c@@ -2258,7 +2258,7 @@ int testapp_too_many_frags(struct test_spec *test) max_frags += 1; } - pkts = calloc(2 * max_frags + 2, sizeof(struct pkt)); + pkts = calloc(2 * max_frags + 3, sizeof(struct pkt)); if (!pkts) return TEST_FAILURE;
@@ -2279,21 +2279,29 @@ int testapp_too_many_frags(struct test_spec *test) /* An invalid packet with the max amount of frags but signals packet * continues on the last frag */ - for (i = max_frags + 1; i < 2 * max_frags + 1; i++) { + for (i = max_frags + 1; i < 2 * max_frags + 2; i++) { pkts[i].len = MIN_PKT_SIZE; pkts[i].options = XDP_PKT_CONTD; - pkts[i].valid = false; + pkts[i].valid = true; } + pkts[2 * max_frags + 1].options = 0; /* Valid packet for synch */ - pkts[2 * max_frags + 1].len = MIN_PKT_SIZE; - pkts[2 * max_frags + 1].valid = true; + pkts[2 * max_frags + 2].len = MIN_PKT_SIZE; + pkts[2 * max_frags + 2].valid = true; - if (pkt_stream_generate_custom(test, pkts, 2 * max_frags + 2)) { + if (pkt_stream_generate_custom(test, pkts, 2 * max_frags + 3)) { free(pkts); return TEST_FAILURE; } + /* The generated Tx stream must keep the too-big packet valid so that + * __send_pkts() accounts its descriptors in outstanding_tx. The Rx + * stream, however, must not expect this packet on the wire. + */ + test->ifobj_rx->xsk->pkt_stream->pkts[2].valid = false; + test->ifobj_rx->xsk->pkt_stream->nb_valid_entries--; + ret = testapp_validate_traffic(test); free(pkts); return ret;
--
2.43.0