On Mon Jun 22, 2026 at 9:40 PM EDT, Sun Jian wrote: > 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 <[email protected]>
Reviewed-by: Emil Tsalapatis <[email protected]> > --- > > v4: > - Send only the selftest patch; the fix patch has been applied to bpf/master. > - Initialize data_out buffers to avoid reading uninitialized stack memory if > bpf_prog_test_run_opts() fails unexpectedly. > > .../selftests/bpf/prog_tests/prog_run_opts.c | 70 +++++++++++++++++++ > .../selftests/bpf/progs/test_pkt_access.c | 12 ++++ > 2 files changed, 82 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..beb6fa78fd94 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 +24,69 @@ 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)); > + > + 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_partial_err"); > + ASSERT_EQ(topts.data_size_out, sizeof(pkt), "skb_partial_size"); > + ASSERT_OK(memcmp(out, pkt, sizeof(out)), "skb_partial_data"); > +} > + > +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)); > + > + 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_partial_err"); > + ASSERT_EQ(topts.data_size_out, sizeof(pkt), "xdp_partial_size"); > + ASSERT_OK(memcmp(out, pkt, sizeof(out)), "xdp_partial_data"); > +} > + > void test_prog_run_opts(void) > { > struct test_pkt_access *skel; > @@ -69,6 +136,9 @@ 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; > +}
