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From: Kui-Feng Lee <thinker.li@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
	song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Cc: sinquersw@gmail.com, kuifeng@meta.com,
	Kui-Feng Lee <thinker.li@gmail.com>
Subject: [PATCH bpf-next v3 7/7] selftests/bpf: make sure bpf_testmod handling racing link destroying well.
Date: Thu,  9 May 2024 17:29:42 -0700	[thread overview]
Message-ID: <20240510002942.1253354-8-thinker.li@gmail.com> (raw)
In-Reply-To: <20240510002942.1253354-1-thinker.li@gmail.com>

Do detachment from the subsystem after a link being closed/freed.  This
test make sure the pattern implemented by bpf_dummy_do_link_detach() works
correctly.

Refer to bpf_dummy_do_link_detach() in bpf_testmod.c for more details.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 .../bpf/prog_tests/test_struct_ops_module.c   | 44 +++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
index f4000bf04752..3a8cdf440edd 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -362,6 +362,48 @@ static void test_subsystem_detach(void)
 	struct_ops_detach__destroy(skel);
 }
 
+/* A subsystem detaches a link while the link is going to be free. */
+static void test_subsystem_detach_free(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		    .data_in = &pkt_v4,
+		    .data_size_in = sizeof(pkt_v4));
+	struct struct_ops_detach *skel;
+	struct bpf_link *link = NULL;
+	int prog_fd;
+	int err;
+
+	skel = struct_ops_detach__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_detach_open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
+	if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
+		goto cleanup;
+
+	bpf_link__destroy(link);
+
+	prog_fd = bpf_program__fd(skel->progs.start_detach);
+	if (!ASSERT_GE(prog_fd, 0, "start_detach_fd"))
+		goto cleanup;
+
+	/* Do detachment from the registered subsystem */
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "start_detach_run"))
+		goto cleanup;
+
+	/* The link has zeroed refcount value or even has been
+	 * unregistered, so the detachment from the subsystem should fail.
+	 */
+	ASSERT_EQ(topts.retval, (u32)-ENOENT, "start_detach_run_retval");
+
+	/* Sync RCU to make sure the link is freed without any crash */
+	ASSERT_OK(kern_sync_rcu(), "kern_sync_rcu");
+
+cleanup:
+	struct_ops_detach__destroy(skel);
+}
+
 void serial_test_struct_ops_module(void)
 {
 	if (test__start_subtest("struct_ops_load"))
@@ -378,5 +420,7 @@ void serial_test_struct_ops_module(void)
 		test_detach_link();
 	if (test__start_subtest("test_subsystem_detach"))
 		test_subsystem_detach();
+	if (test__start_subtest("test_subsystem_detach_free"))
+		test_subsystem_detach_free();
 }
 
-- 
2.34.1


      parent reply	other threads:[~2024-05-10  0:29 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-10  0:29 [PATCH bpf-next v3 0/7] Notify user space when a struct_ops object is detached/unregistered Kui-Feng Lee
2024-05-10  0:29 ` [PATCH bpf-next v3 1/7] bpf: pass bpf_struct_ops_link to callbacks in bpf_struct_ops Kui-Feng Lee
2024-05-10  0:29 ` [PATCH bpf-next v3 2/7] bpf: enable detaching links of struct_ops objects Kui-Feng Lee
2024-05-21  1:22   ` Martin KaFai Lau
2024-05-21  7:30     ` Kui-Feng Lee
2024-05-21 18:09       ` Martin KaFai Lau
2024-05-10  0:29 ` [PATCH bpf-next v3 3/7] bpf: support epoll from bpf struct_ops links Kui-Feng Lee
2024-05-21  1:26   ` Martin KaFai Lau
2024-05-21  7:31     ` Kui-Feng Lee
2024-05-10  0:29 ` [PATCH bpf-next v3 4/7] bpf: export bpf_link_inc_not_zero Kui-Feng Lee
2024-05-10  0:29 ` [PATCH bpf-next v3 5/7] selftests/bpf: test struct_ops with epoll Kui-Feng Lee
2024-05-10  0:29 ` [PATCH bpf-next v3 6/7] selftests/bpf: detach a struct_ops link from the subsystem managing it Kui-Feng Lee
2024-05-21 22:56   ` Amery Hung
2024-05-22  0:31     ` Kui-Feng Lee
2024-05-22 17:33       ` Amery Hung
2024-05-10  0:29 ` Kui-Feng Lee [this message]

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