On Mon, Jun 15, 2026 at 03:38:56PM +0800, Sun Jian wrote: > Add a test case for BPF_PROG_TEST_RUN with a non-linear skb and a short > data_out buffer. > > The test verifies that test_run returns -ENOSPC, reports the full packet > length through data_size_out, and copies the packet prefix into data_out. > The test uses a 100-byte data_out buffer with a 64-byte linear head, so the > expected output spans both the skb head and the first fragment. > > Signed-off-by: Sun Jian <[email protected]> > --- > .../selftests/bpf/prog_tests/skb_load_bytes.c | 35 +++++++++++++++++++ > 1 file changed, 35 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/skb_load_bytes.c > b/tools/testing/selftests/bpf/prog_tests/skb_load_bytes.c > index d7f83c0a40a5..134be0ea8ed7 100644 > --- a/tools/testing/selftests/bpf/prog_tests/skb_load_bytes.c > +++ b/tools/testing/selftests/bpf/prog_tests/skb_load_bytes.c > @@ -3,6 +3,39 @@ > #include <network_helpers.h> > #include "skb_load_bytes.skel.h" > > +#define NONLINEAR_PKT_LEN 9000 > +#define NONLINEAR_HEAD_LEN 64 > +#define SHORT_OUT_LEN 100 > + > +static void test_nonlinear_data_out_partial(int prog_fd) > +{ > + LIBBPF_OPTS(bpf_test_run_opts, tattr); > + __u8 pkt[NONLINEAR_PKT_LEN]; > + __u8 out[SHORT_OUT_LEN]; > + struct __sk_buff skb = {}; > + int err, i; > + > + for (i = 0; i < sizeof(pkt); i++) > + pkt[i] = i & 0xff; > + > + memset(out, 0xa5, sizeof(out)); > + > + skb.data_end = NONLINEAR_HEAD_LEN; > + > + tattr.data_in = pkt; > + tattr.data_size_in = sizeof(pkt); > + tattr.data_out = out; > + tattr.data_size_out = sizeof(out); > + tattr.ctx_in = &skb; > + tattr.ctx_size_in = sizeof(skb); > + > + err = bpf_prog_test_run_opts(prog_fd, &tattr); > + > + ASSERT_EQ(err, -ENOSPC, "nonlinear_partial_err"); > + ASSERT_EQ(tattr.data_size_out, sizeof(pkt), > "nonlinear_partial_data_size_out"); > + ASSERT_OK(memcmp(out, pkt, sizeof(out)), "nonlinear_partial_data_out"); > +} > + > void test_skb_load_bytes(void) > { > struct skb_load_bytes *skel; > @@ -40,6 +73,8 @@ void test_skb_load_bytes(void) > if (!ASSERT_EQ(test_result, 0, "offset 10")) > goto out; > > + test_nonlinear_data_out_partial(prog_fd); > +
Maybe prog_tests/prog_run_opts.c would be a better place to cover this? test_skb_load_bytes() is meant to cover the bpf_skb_load_bytes helper. > out: > skb_load_bytes__destroy(skel); > } > -- > 2.43.0 >
