Add a test case for the tracepoint of xdp attaching failure by bpf
tracepoint when attach XDP to a device with invalid flags option.
The bpf tracepoint retrieves error message from the tracepoint, and
then put the error message to a perf buffer. The testing code receives
error message from perf buffer, and then ASSERT "Invalid XDP flags for
BPF link attachment".
Signed-off-by: Leon Hwang <[email protected]>
---
.../selftests/bpf/prog_tests/xdp_attach.c | 65 +++++++++++++++++++
.../bpf/progs/test_xdp_attach_fail.c | 52 +++++++++++++++
2 files changed, 117 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
index fa3cac5488f5d..99f8d03f3c8bd 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
+#include "test_xdp_attach_fail.skel.h"
#define IFINDEX_LO 1
#define XDP_FLAGS_REPLACE (1U << 4)
@@ -85,10 +86,74 @@ static void test_xdp_attach(const char *file)
bpf_object__close(obj1);
}
+struct xdp_errmsg {
+ char msg[64];
+};
+
+static void on_xdp_errmsg(void *ctx, int cpu, void *data, __u32 size)
+{
+ struct xdp_errmsg *ctx_errmg = ctx, *tp_errmsg = data;
+
+ memcpy(&ctx_errmg->msg, &tp_errmsg->msg, size);
+}
+
+static const char tgt_errmsg[] = "Invalid XDP flags for BPF link attachment";
+
+static void test_xdp_attach_fail(const char *file)
+{
+ __u32 duration = 0;
+ int err, fd_xdp, fd_link_xdp;
+ struct bpf_object *obj = NULL;
+ struct test_xdp_attach_fail *skel = NULL;
+ struct bpf_link *link = NULL;
+ struct perf_buffer *pb = NULL;
+ struct xdp_errmsg errmsg = {};
+
+ LIBBPF_OPTS(bpf_link_create_opts, opts);
+
+ skel = test_xdp_attach_fail__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "test_xdp_attach_fail_skel"))
+ goto out_close;
+
+ link = bpf_program__attach_tracepoint(skel->progs.tp__xdp__bpf_xdp_link_attach_failed,
+ "xdp", "bpf_xdp_link_attach_failed");
+ if (!ASSERT_OK_PTR(link, "attach_tp"))
+ goto out_close;
+
+ /* set up perf buffer */
+ pb = perf_buffer__new(bpf_map__fd(skel->maps.xdp_errmsg_pb), 1,
+ on_xdp_errmsg, NULL, &errmsg, NULL);
+
+ err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &fd_xdp);
+ if (CHECK_FAIL(err))
+ goto out_close;
+
+ opts.flags = 0xFF; // invalid flags to fail to attach XDP prog
+ fd_link_xdp = bpf_link_create(fd_xdp, IFINDEX_LO, BPF_XDP, &opts);
+ if (CHECK(fd_link_xdp != -22, "bpf_link_create_failed",
+ "created link fd: %d\n", fd_link_xdp))
+ goto out_close;
+
+ /* read perf buffer */
+ err = perf_buffer__poll(pb, 100);
+ if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err))
+ goto out_close;
+
+ ASSERT_STRNEQ((const char *) errmsg.msg, tgt_errmsg,
+ 42 /* strlen(tgt_errmsg) */, "check error message");
+
+out_close:
+ perf_buffer__free(pb);
+ bpf_object__close(obj);
+ test_xdp_attach_fail__destroy(skel);
+}
+
void serial_test_xdp_attach(void)
{
if (test__start_subtest("xdp_attach"))
test_xdp_attach("./test_xdp.bpf.o");
if (test__start_subtest("xdp_attach_dynptr"))
test_xdp_attach("./test_xdp_dynptr.bpf.o");
+ if (test__start_subtest("xdp_attach_failed"))
+ test_xdp_attach_fail("./xdp_dummy.bpf.o");
}
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c
new file mode 100644
index 0000000000000..64baf73910a0e
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Leon Hwang */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct xdp_errmsg {
+ char msg[64];
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+ __uint(key_size, sizeof(__u32));
+ __uint(value_size, sizeof(__u32));
+} xdp_errmsg_pb SEC(".maps");
+
+struct xdp_attach_error_ctx {
+ unsigned long unused;
+
+ /*
+ * bpf does not support tracepoint __data_loc directly.
+ *
+ * Actually, this field is a 32 bit integer whose value encodes
+ * information on where to find the actual data. The first 2 bytes is
+ * the size of the data. The last 2 bytes is the offset from the start
+ * of the tracepoint struct where the data begins.
+ * -- https://github.com/iovisor/bpftrace/pull/1542
+ */
+ __u32 msg; // __data_loc char[] msg;
+};
+
+/*
+ * Catch up the error message at the tracepoint.
+ */
+
+SEC("tp/xdp/bpf_xdp_link_attach_failed")
+int tp__xdp__bpf_xdp_link_attach_failed(struct xdp_attach_error_ctx *ctx)
+{
+ struct xdp_errmsg errmsg;
+ char *msg = (void *)(__u64) ((void *) ctx + (__u16) ctx->msg);
+
+ bpf_probe_read_kernel_str(&errmsg.msg, sizeof(errmsg.msg), msg);
+ bpf_perf_event_output(ctx, &xdp_errmsg_pb, BPF_F_CURRENT_CPU, &errmsg,
+ sizeof(errmsg));
+ return 0;
+}
+
+/*
+ * Reuse the XDP program in xdp_dummy.c.
+ */
+
+char LICENSE[] SEC("license") = "GPL";
--
2.41.0
On 7/20/23 8:52 AM, Leon Hwang wrote:
> Add a test case for the tracepoint of xdp attaching failure by bpf
> tracepoint when attach XDP to a device with invalid flags option.
>
> The bpf tracepoint retrieves error message from the tracepoint, and
> then put the error message to a perf buffer. The testing code receives
> error message from perf buffer, and then ASSERT "Invalid XDP flags for
> BPF link attachment".
>
> Signed-off-by: Leon Hwang <[email protected]>
> ---
> .../selftests/bpf/prog_tests/xdp_attach.c | 65 +++++++++++++++++++
> .../bpf/progs/test_xdp_attach_fail.c | 52 +++++++++++++++
> 2 files changed, 117 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
> index fa3cac5488f5d..99f8d03f3c8bd 100644
> --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <test_progs.h>
> +#include "test_xdp_attach_fail.skel.h"
>
> #define IFINDEX_LO 1
> #define XDP_FLAGS_REPLACE (1U << 4)
> @@ -85,10 +86,74 @@ static void test_xdp_attach(const char *file)
> bpf_object__close(obj1);
> }
>
> +struct xdp_errmsg {
> + char msg[64];
> +};
> +
> +static void on_xdp_errmsg(void *ctx, int cpu, void *data, __u32 size)
> +{
> + struct xdp_errmsg *ctx_errmg = ctx, *tp_errmsg = data;
> +
> + memcpy(&ctx_errmg->msg, &tp_errmsg->msg, size);
> +}
> +
> +static const char tgt_errmsg[] = "Invalid XDP flags for BPF link attachment";
> +
> +static void test_xdp_attach_fail(const char *file)
The test crashed:
https://github.com/kernel-patches/bpf/actions/runs/5672753995/job/15373384795#step:6:8037
Please monitor the CI test result in the future.
> +{
> + __u32 duration = 0;
> + int err, fd_xdp, fd_link_xdp;
> + struct bpf_object *obj = NULL;
> + struct test_xdp_attach_fail *skel = NULL;
> + struct bpf_link *link = NULL;
> + struct perf_buffer *pb = NULL;
> + struct xdp_errmsg errmsg = {};
> +
> + LIBBPF_OPTS(bpf_link_create_opts, opts);
> +
> + skel = test_xdp_attach_fail__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "test_xdp_attach_fail_skel"))
> + goto out_close;
> +
> + link = bpf_program__attach_tracepoint(skel->progs.tp__xdp__bpf_xdp_link_attach_failed,
> + "xdp", "bpf_xdp_link_attach_failed");
> + if (!ASSERT_OK_PTR(link, "attach_tp"))
> + goto out_close;
> +
> + /* set up perf buffer */
> + pb = perf_buffer__new(bpf_map__fd(skel->maps.xdp_errmsg_pb), 1,
> + on_xdp_errmsg, NULL, &errmsg, NULL);
> +
> + err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &fd_xdp);
> + if (CHECK_FAIL(err))
> + goto out_close;
> +
> + opts.flags = 0xFF; // invalid flags to fail to attach XDP prog
> + fd_link_xdp = bpf_link_create(fd_xdp, IFINDEX_LO, BPF_XDP, &opts);
> + if (CHECK(fd_link_xdp != -22, "bpf_link_create_failed",
Please stay with the ASSERT_* macro.
--
pw-bot: cr
On 27/7/23 05:52, Martin KaFai Lau wrote:
> On 7/20/23 8:52 AM, Leon Hwang wrote:
>> Add a test case for the tracepoint of xdp attaching failure by bpf
>> tracepoint when attach XDP to a device with invalid flags option.
>>
>> The bpf tracepoint retrieves error message from the tracepoint, and
>> then put the error message to a perf buffer. The testing code receives
>> error message from perf buffer, and then ASSERT "Invalid XDP flags for
>> BPF link attachment".
>>
>> Signed-off-by: Leon Hwang <[email protected]>
>> ---
>> .../selftests/bpf/prog_tests/xdp_attach.c | 65 +++++++++++++++++++
>> .../bpf/progs/test_xdp_attach_fail.c | 52 +++++++++++++++
>> 2 files changed, 117 insertions(+)
>> create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
>> index fa3cac5488f5d..99f8d03f3c8bd 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c
>> @@ -1,5 +1,6 @@
>> // SPDX-License-Identifier: GPL-2.0
>> #include <test_progs.h>
>> +#include "test_xdp_attach_fail.skel.h"
>> #define IFINDEX_LO 1
>> #define XDP_FLAGS_REPLACE (1U << 4)
>> @@ -85,10 +86,74 @@ static void test_xdp_attach(const char *file)
>> bpf_object__close(obj1);
>> }
>> +struct xdp_errmsg {
>> + char msg[64];
>> +};
>> +
>> +static void on_xdp_errmsg(void *ctx, int cpu, void *data, __u32 size)
>> +{
>> + struct xdp_errmsg *ctx_errmg = ctx, *tp_errmsg = data;
>> +
>> + memcpy(&ctx_errmg->msg, &tp_errmsg->msg, size);
>> +}
>> +
>> +static const char tgt_errmsg[] = "Invalid XDP flags for BPF link attachment";
>> +
>> +static void test_xdp_attach_fail(const char *file)
>
> The test crashed: https://github.com/kernel-patches/bpf/actions/runs/5672753995/job/15373384795#step:6:8037
>
> Please monitor the CI test result in the future.
>
Get it. I'll fix it as soon as possible. And make sure all the CI tests are passed.
>> +{
>> + __u32 duration = 0;
>> + int err, fd_xdp, fd_link_xdp;
>> + struct bpf_object *obj = NULL;
>> + struct test_xdp_attach_fail *skel = NULL;
>> + struct bpf_link *link = NULL;
>> + struct perf_buffer *pb = NULL;
>> + struct xdp_errmsg errmsg = {};
>> +
>> + LIBBPF_OPTS(bpf_link_create_opts, opts);
>> +
>> + skel = test_xdp_attach_fail__open_and_load();
>> + if (!ASSERT_OK_PTR(skel, "test_xdp_attach_fail_skel"))
>> + goto out_close;
>> +
>> + link = bpf_program__attach_tracepoint(skel->progs.tp__xdp__bpf_xdp_link_attach_failed,
>> + "xdp", "bpf_xdp_link_attach_failed");
>> + if (!ASSERT_OK_PTR(link, "attach_tp"))
>> + goto out_close;
>> +
>> + /* set up perf buffer */
>> + pb = perf_buffer__new(bpf_map__fd(skel->maps.xdp_errmsg_pb), 1,
>> + on_xdp_errmsg, NULL, &errmsg, NULL);
>> +
>> + err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &fd_xdp);
>> + if (CHECK_FAIL(err))
>> + goto out_close;
>> +
>> + opts.flags = 0xFF; // invalid flags to fail to attach XDP prog
>> + fd_link_xdp = bpf_link_create(fd_xdp, IFINDEX_LO, BPF_XDP, &opts);
>> + if (CHECK(fd_link_xdp != -22, "bpf_link_create_failed",
>
> Please stay with the ASSERT_* macro.
>
Get it.
Thanks,
Leon