* [PATCH bpf v4] selftests/bpf: Cover partial copy of non-linear test_run output
@ 2026-06-23 1:40 Sun Jian
2026-06-23 23:18 ` Emil Tsalapatis
0 siblings, 1 reply; 2+ messages in thread
From: Sun Jian @ 2026-06-23 1:40 UTC (permalink / raw)
To: bpf
Cc: netdev, linux-kselftest, linux-kernel, ast, daniel, andrii,
martin.lau, paul.chaignon, Sun Jian
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 <sun.jian.kdev@gmail.com>
---
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;
+}
--
2.43.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf v4] selftests/bpf: Cover partial copy of non-linear test_run output
2026-06-23 1:40 [PATCH bpf v4] selftests/bpf: Cover partial copy of non-linear test_run output Sun Jian
@ 2026-06-23 23:18 ` Emil Tsalapatis
0 siblings, 0 replies; 2+ messages in thread
From: Emil Tsalapatis @ 2026-06-23 23:18 UTC (permalink / raw)
To: Sun Jian, bpf
Cc: netdev, linux-kselftest, linux-kernel, ast, daniel, andrii,
martin.lau, paul.chaignon
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 <sun.jian.kdev@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
> ---
>
> 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;
> +}
^ permalink raw reply [flat|nested] 2+ messages in thread
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