[PATCH bpf v2 2/2] selftests/bpf: Cover partial copy of non-linear test_run output
From: Sun Jian <hidden>
Date: 2026-06-16 09:31:47
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
prog_run_opts already verifies that BPF_PROG_TEST_RUN returns -ENOSPC for a short data_out buffer while still reporting the full output size through data_size_out. Add the same coverage for non-linear test_run output. Use pass-through TC and XDP programs with a 9000-byte packet, a 64-byte linear data area, and a 100-byte data_out buffer. The expected output spans both the linear data and the first fragment. Verify that test_run returns -ENOSPC, reports the full packet length through data_size_out, and copies the packet prefix into data_out for both non-linear skb and XDP frags paths. Signed-off-by: Sun Jian <redacted> --- .../selftests/bpf/prog_tests/prog_run_opts.c | 72 +++++++++++++++++++ .../selftests/bpf/progs/test_pkt_access.c | 12 ++++ 2 files changed, 84 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/prog_run_opts.c b/tools/testing/selftests/bpf/prog_tests/prog_run_opts.c
index 01f1d1b6715a..71af1ff02023 100644
--- a/tools/testing/selftests/bpf/prog_tests/prog_run_opts.c
+++ b/tools/testing/selftests/bpf/prog_tests/prog_run_opts.c@@ -4,6 +4,10 @@ #include "test_pkt_access.skel.h" +#define NONLINEAR_PKT_LEN 9000 +#define NONLINEAR_LINEAR_DATA_LEN 64 +#define SHORT_OUT_LEN 100 + static const __u32 duration; static void check_run_cnt(int prog_fd, __u64 run_cnt)
@@ -20,6 +24,71 @@ static void check_run_cnt(int prog_fd, __u64 run_cnt) "incorrect number of repetitions, want %llu have %llu\n", run_cnt, info.run_cnt); } +static void init_pkt(__u8 *pkt, size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) + pkt[i] = i & 0xff; +} + +static void test_skb_nonlinear_data_out_partial(struct test_pkt_access *skel) +{ + LIBBPF_OPTS(bpf_test_run_opts, topts); + __u8 pkt[NONLINEAR_PKT_LEN]; + __u8 out[SHORT_OUT_LEN]; + struct __sk_buff skb = {}; + int prog_fd, err; + + init_pkt(pkt, sizeof(pkt)); + memset(out, 0xa5, sizeof(out)); + + skb.data_end = NONLINEAR_LINEAR_DATA_LEN; + + topts.data_in = pkt; + topts.data_size_in = sizeof(pkt); + topts.data_out = out; + topts.data_size_out = sizeof(out); + topts.ctx_in = &skb; + topts.ctx_size_in = sizeof(skb); + + prog_fd = bpf_program__fd(skel->progs.tc_pass_prog); + err = bpf_prog_test_run_opts(prog_fd, &topts); + + ASSERT_EQ(err, -ENOSPC, "skb_nonlinear_partial_err"); + ASSERT_EQ(topts.data_size_out, sizeof(pkt), "skb_nonlinear_partial_data_size_out"); + ASSERT_OK(memcmp(out, pkt, sizeof(out)), "skb_nonlinear_partial_data_out"); +} + +static void test_xdp_nonlinear_data_out_partial(struct test_pkt_access *skel) +{ + LIBBPF_OPTS(bpf_test_run_opts, topts); + __u8 pkt[NONLINEAR_PKT_LEN]; + __u8 out[SHORT_OUT_LEN]; + struct xdp_md ctx = {}; + int prog_fd, err; + + init_pkt(pkt, sizeof(pkt)); + memset(out, 0xa5, sizeof(out)); + + ctx.data = 0; + ctx.data_end = NONLINEAR_LINEAR_DATA_LEN; + + topts.data_in = pkt; + topts.data_size_in = sizeof(pkt); + topts.data_out = out; + topts.data_size_out = sizeof(out); + topts.ctx_in = &ctx; + topts.ctx_size_in = sizeof(ctx); + + prog_fd = bpf_program__fd(skel->progs.xdp_frags_pass_prog); + err = bpf_prog_test_run_opts(prog_fd, &topts); + + ASSERT_EQ(err, -ENOSPC, "xdp_nonlinear_partial_err"); + ASSERT_EQ(topts.data_size_out, sizeof(pkt), "xdp_nonlinear_partial_data_size_out"); + ASSERT_OK(memcmp(out, pkt, sizeof(out)), "xdp_nonlinear_partial_data_out"); +} + void test_prog_run_opts(void) { struct test_pkt_access *skel;
@@ -69,6 +138,9 @@ void test_prog_run_opts(void) run_cnt += topts.repeat; check_run_cnt(prog_fd, run_cnt); + test_skb_nonlinear_data_out_partial(skel); + test_xdp_nonlinear_data_out_partial(skel); + cleanup: if (skel) test_pkt_access__destroy(skel);
diff --git a/tools/testing/selftests/bpf/progs/test_pkt_access.c b/tools/testing/selftests/bpf/progs/test_pkt_access.c
index bce7173152c6..cd284401eebd 100644
--- a/tools/testing/selftests/bpf/progs/test_pkt_access.c
+++ b/tools/testing/selftests/bpf/progs/test_pkt_access.c@@ -150,3 +150,15 @@ int test_pkt_access(struct __sk_buff *skb) return TC_ACT_UNSPEC; } + +SEC("tc") +int tc_pass_prog(struct __sk_buff *skb) +{ + return TC_ACT_OK; +} + +SEC("xdp.frags") +int xdp_frags_pass_prog(struct xdp_md *ctx) +{ + return XDP_PASS; +}
--
2.43.0