BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Alexei Starovoitov <ast@kernel.org>
To: <davem@davemloft.net>
Cc: <daniel@iogearbox.net>, <x86@kernel.org>,
	<netdev@vger.kernel.org>, <bpf@vger.kernel.org>,
	<kernel-team@fb.com>
Subject: [PATCH v3 bpf-next 18/18] selftests/bpf: Add a test for attaching BPF prog to another BPF prog and subprog
Date: Thu, 7 Nov 2019 22:40:39 -0800
Message-ID: <20191108064039.2041889-19-ast@kernel.org> (raw)
In-Reply-To: <20191108064039.2041889-1-ast@kernel.org>

Add a test that attaches one FEXIT program to main sched_cls networking program
and two other FEXIT programs to subprograms. All three tracing programs
access return values and skb->len of networking program and subprograms.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 .../selftests/bpf/prog_tests/fexit_bpf2bpf.c  | 76 ++++++++++++++++
 .../selftests/bpf/progs/fexit_bpf2bpf.c       | 91 +++++++++++++++++++
 2 files changed, 167 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
 create mode 100644 tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c

diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
new file mode 100644
index 000000000000..15c7378362dd
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook */
+#include <test_progs.h>
+
+#define PROG_CNT 3
+
+void test_fexit_bpf2bpf(void)
+{
+	const char *prog_name[PROG_CNT] = {
+		"fexit/test_pkt_access",
+		"fexit/test_pkt_access_subprog1",
+		"fexit/test_pkt_access_subprog2",
+	};
+	struct bpf_object *obj = NULL, *pkt_obj;
+	int err, pkt_fd, i;
+	struct bpf_link *link[PROG_CNT] = {};
+	struct bpf_program *prog[PROG_CNT];
+	__u32 duration, retval;
+	struct bpf_map *data_map;
+	const int zero = 0;
+	u64 result[PROG_CNT];
+
+	err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_UNSPEC,
+			    &pkt_obj, &pkt_fd);
+	if (CHECK(err, "prog_load sched cls", "err %d errno %d\n", err, errno))
+		return;
+	DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
+			    .attach_prog_fd = pkt_fd,
+			   );
+
+	obj = bpf_object__open_file("./fexit_bpf2bpf.o", &opts);
+	if (CHECK(IS_ERR_OR_NULL(obj), "obj_open",
+		  "failed to open fexit_bpf2bpf: %ld\n",
+		  PTR_ERR(obj)))
+		goto close_prog;
+
+	err = bpf_object__load(obj);
+	if (CHECK(err, "obj_load", "err %d\n", err))
+		goto close_prog;
+
+	for (i = 0; i < PROG_CNT; i++) {
+		prog[i] = bpf_object__find_program_by_title(obj, prog_name[i]);
+		if (CHECK(!prog[i], "find_prog", "prog %s not found\n", prog_name[i]))
+			goto close_prog;
+		link[i] = bpf_program__attach_trace(prog[i]);
+		if (CHECK(IS_ERR(link[i]), "attach_trace", "failed to link\n"))
+			goto close_prog;
+	}
+	data_map = bpf_object__find_map_by_name(obj, "fexit_bp.bss");
+	if (CHECK(!data_map, "find_data_map", "data map not found\n"))
+		goto close_prog;
+
+	err = bpf_prog_test_run(pkt_fd, 1, &pkt_v6, sizeof(pkt_v6),
+				NULL, NULL, &retval, &duration);
+	CHECK(err || retval, "ipv6",
+	      "err %d errno %d retval %d duration %d\n",
+	      err, errno, retval, duration);
+
+	err = bpf_map_lookup_elem(bpf_map__fd(data_map), &zero, &result);
+	if (CHECK(err, "get_result",
+		  "failed to get output data: %d\n", err))
+		goto close_prog;
+
+	for (i = 0; i < PROG_CNT; i++)
+		if (CHECK(result[i] != 1, "result", "fexit_bpf2bpf failed err %ld\n",
+			  result[i]))
+			goto close_prog;
+
+close_prog:
+	for (i = 0; i < PROG_CNT; i++)
+		if (!IS_ERR_OR_NULL(link[i]))
+			bpf_link__destroy(link[i]);
+	if (!IS_ERR_OR_NULL(obj))
+		bpf_object__close(obj);
+	bpf_object__close(pkt_obj);
+}
diff --git a/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
new file mode 100644
index 000000000000..69b592217e99
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/fexit_bpf2bpf.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook */
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+struct sk_buff {
+	unsigned int len;
+};
+
+struct args {
+	struct sk_buff *skb;
+	ks32 ret;
+};
+static volatile __u64 test_result;
+SEC("fexit/test_pkt_access")
+int test_main(struct args *ctx)
+{
+	struct sk_buff *skb = ctx->skb;
+	int len;
+
+	__builtin_preserve_access_index(({
+		len = skb->len;
+	}));
+	if (len != 74 || ctx->ret != 0)
+		return 0;
+	test_result = 1;
+	return 0;
+}
+
+struct args_subprog1 {
+	struct sk_buff *skb;
+	ks32 ret;
+};
+static volatile __u64 test_result_subprog1;
+SEC("fexit/test_pkt_access_subprog1")
+int test_subprog1(struct args_subprog1 *ctx)
+{
+	struct sk_buff *skb = ctx->skb;
+	int len;
+
+	__builtin_preserve_access_index(({
+		len = skb->len;
+	}));
+	if (len != 74 || ctx->ret != 148)
+		return 0;
+	test_result_subprog1 = 1;
+	return 0;
+}
+
+/* Though test_pkt_access_subprog2() is defined in C as:
+ * static __attribute__ ((noinline))
+ * int test_pkt_access_subprog2(int val, volatile struct __sk_buff *skb)
+ * {
+ *     return skb->len * val;
+ * }
+ * llvm optimizations remove 'int val' argument and generate BPF assembly:
+ *   r0 = *(u32 *)(r1 + 0)
+ *   w0 <<= 1
+ *   exit
+ * In such case the verifier falls back to conservative and
+ * tracing program can access arguments and return value as u64
+ * instead of accurate types.
+ */
+struct args_subprog2 {
+	ku64 args[5];
+	ku64 ret;
+};
+static volatile __u64 test_result_subprog2;
+SEC("fexit/test_pkt_access_subprog2")
+int test_subprog2(struct args_subprog2 *ctx)
+{
+	struct sk_buff *skb = (void *)ctx->args[0];
+	__u64 ret;
+	int len;
+
+	bpf_probe_read(&len, sizeof(len),
+		       __builtin_preserve_access_index(&skb->len));
+
+	ret = ctx->ret;
+	/* bpf_prog_load() loads "test_pkt_access.o" with BPF_F_TEST_RND_HI32
+	 * which randomizes upper 32 bits after BPF_ALU32 insns.
+	 * Hence after 'w0 <<= 1' upper bits of $rax are random.
+	 * That is expected and correct. Trim them.
+	 */
+	ret = (__u32) ret;
+	if (len != 74 || ret != 148)
+		return 0;
+	test_result_subprog2 = 1;
+	return 0;
+}
+char _license[] SEC("license") = "GPL";
-- 
2.23.0


  parent reply index

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-08  6:40 [PATCH v3 bpf-next 00/18] Introduce BPF trampoline Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 01/18] bpf: refactor x86 JIT into helpers Alexei Starovoitov
2019-11-08 19:27   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 02/18] bpf: Add bpf_arch_text_poke() helper Alexei Starovoitov
2019-11-08  6:56   ` Song Liu
2019-11-08  8:23   ` Björn Töpel
2019-11-08 14:09     ` Alexei Starovoitov
2019-11-08  9:11   ` Peter Zijlstra
2019-11-08  9:36     ` Peter Zijlstra
2019-11-08 13:41       ` Alexei Starovoitov
2019-11-08 19:32         ` Alexei Starovoitov
2019-11-08 21:36           ` Peter Zijlstra
2019-11-08 21:39             ` David Miller
2019-11-11  8:14               ` Peter Zijlstra
2019-11-11 10:21                 ` Daniel Borkmann
2019-11-11 16:10                 ` Jonathan Corbet
2019-11-08 23:05             ` Alexei Starovoitov
2019-11-10 10:54               ` Thomas Gleixner
2019-11-08  6:40 ` [PATCH v3 bpf-next 03/18] bpf: Introduce BPF trampoline Alexei Starovoitov
2019-11-08  7:04   ` Song Liu
2019-11-08  6:40 ` [PATCH v3 bpf-next 04/18] libbpf: Introduce btf__find_by_name_kind() Alexei Starovoitov
2019-11-08  7:05   ` Song Liu
2019-11-08 19:21   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 05/18] libbpf: Add support to attach to fentry/fexit tracing progs Alexei Starovoitov
2019-11-08  7:12   ` Song Liu
2019-11-08 19:44   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 06/18] selftest/bpf: Simple test for fentry/fexit Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 07/18] bpf: Add kernel test functions for fentry testing Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 08/18] selftests/bpf: Add test for BPF trampoline Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 09/18] selftests/bpf: Add fexit tests " Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 10/18] selftests/bpf: Add combined fentry/fexit test Alexei Starovoitov
2019-11-08  7:14   ` Song Liu
2019-11-08  6:40 ` [PATCH v3 bpf-next 11/18] selftests/bpf: Add stress test for maximum number of progs Alexei Starovoitov
2019-11-08  7:24   ` Song Liu
2019-11-08  6:40 ` [PATCH v3 bpf-next 12/18] bpf: Reserve space for BPF trampoline in BPF programs Alexei Starovoitov
2019-11-08  7:25   ` Song Liu
2019-11-08  6:40 ` [PATCH v3 bpf-next 13/18] bpf: Fix race in btf_resolve_helper_id() Alexei Starovoitov
2019-11-08  7:32   ` Song Liu
2019-11-08 19:58   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 14/18] bpf: Compare BTF types of functions arguments with actual types Alexei Starovoitov
2019-11-08 17:28   ` Song Liu
2019-11-08 17:32     ` Song Liu
2019-11-08 17:57       ` Alexei Starovoitov
2019-11-08 17:59         ` Song Liu
2019-11-08 23:46   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 15/18] bpf: Support attaching tracing BPF program to other BPF programs Alexei Starovoitov
2019-11-08 18:49   ` Song Liu
2019-11-08 18:59     ` Alexei Starovoitov
2019-11-08 20:17   ` Toke Høiland-Jørgensen
2019-11-08 21:14     ` Alexei Starovoitov
2019-11-08 21:32       ` Toke Høiland-Jørgensen
2019-11-10  7:17   ` Andrii Nakryiko
2019-11-11 23:04     ` Alexei Starovoitov
2019-11-12  4:38       ` Andrii Nakryiko
2019-11-12  4:47         ` Alexei Starovoitov
2019-11-08  6:40 ` [PATCH v3 bpf-next 16/18] libbpf: Add support for attaching BPF programs " Alexei Starovoitov
2019-11-08 18:57   ` Song Liu
2019-11-08 19:13     ` Alexei Starovoitov
2019-11-08 19:14       ` Song Liu
2019-11-10 16:56   ` Andrii Nakryiko
2019-11-08  6:40 ` [PATCH v3 bpf-next 17/18] selftests/bpf: Extend test_pkt_access test Alexei Starovoitov
2019-11-08 19:03   ` Song Liu
2019-11-10 16:58   ` Andrii Nakryiko
2019-11-08  6:40 ` Alexei Starovoitov [this message]
2019-11-08 19:13   ` [PATCH v3 bpf-next 18/18] selftests/bpf: Add a test for attaching BPF prog to another BPF prog and subprog Song Liu
2019-11-10 17:04   ` Andrii Nakryiko
2019-11-11 23:07     ` Alexei Starovoitov

Reply instructions:

You may reply publically 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=20191108064039.2041889-19-ast@kernel.org \
    --to=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=kernel-team@fb.com \
    --cc=netdev@vger.kernel.org \
    --cc=x86@kernel.org \
    /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

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org
	public-inbox-index bpf

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git