From: Leon Hwang <hffilwlqm@gmail.com>
To: ast@kernel.org
Cc: daniel@iogearbox.net, john.fastabend@gmail.com,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, davem@davemloft.net,
edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
hawk@kernel.org, hffilwlqm@gmail.com, tangyeechou@gmail.com,
kernel-patches-bot@fb.com, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: [RESEND PATCH bpf-next v3 2/2] selftests/bpf: Add testcase for xdp attaching failure tracepoint
Date: Thu, 20 Jul 2023 23:52:28 +0800 [thread overview]
Message-ID: <20230720155228.5708-3-hffilwlqm@gmail.com> (raw)
In-Reply-To: <20230720155228.5708-1-hffilwlqm@gmail.com>
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 <hffilwlqm@gmail.com>
---
.../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
next prev parent reply other threads:[~2023-07-20 15:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-20 15:52 [RESEND PATCH bpf-next v3 0/2] bpf, xdp: Add tracepoint to xdp attaching failure Leon Hwang
2023-07-20 15:52 ` [RESEND PATCH bpf-next v3 1/2] " Leon Hwang
2023-07-20 15:52 ` Leon Hwang [this message]
2023-07-26 21:52 ` [RESEND PATCH bpf-next v3 2/2] selftests/bpf: Add testcase for xdp attaching failure tracepoint Martin KaFai Lau
2023-07-27 1:57 ` Leon Hwang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230720155228.5708-3-hffilwlqm@gmail.com \
--to=hffilwlqm@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=haoluo@google.com \
--cc=hawk@kernel.org \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kernel-patches-bot@fb.com \
--cc=kpsingh@kernel.org \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=sdf@google.com \
--cc=song@kernel.org \
--cc=tangyeechou@gmail.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).