selftests/bpf: Add tests for reference state fixes for callbacks

These are regression tests to ensure we don't end up in invalid runtime
state for helpers that execute callbacks multiple times. It exercises
the fixes to verifier callback handling for reference state in previous
patches.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220823013226.24988-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/cb_refs.c b/tools/testing/selftests/bpf/prog_tests/cb_refs.c
new file mode 100644
index 000000000000..3bff680de16c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/cb_refs.c
@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "bpf/libbpf.h"
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "cb_refs.skel.h"
+
+static char log_buf[1024 * 1024];
+
+struct {
+	const char *prog_name;
+	const char *err_msg;
+} cb_refs_tests[] = {
+	{ "underflow_prog", "reference has not been acquired before" },
+	{ "leak_prog", "Unreleased reference" },
+	{ "nested_cb", "Unreleased reference id=4 alloc_insn=2" }, /* alloc_insn=2{4,5} */
+	{ "non_cb_transfer_ref", "Unreleased reference id=4 alloc_insn=1" }, /* alloc_insn=1{1,2} */
+};
+
+void test_cb_refs(void)
+{
+	LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf,
+						.kernel_log_size = sizeof(log_buf),
+						.kernel_log_level = 1);
+	struct bpf_program *prog;
+	struct cb_refs *skel;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(cb_refs_tests); i++) {
+		LIBBPF_OPTS(bpf_test_run_opts, run_opts,
+			.data_in = &pkt_v4,
+			.data_size_in = sizeof(pkt_v4),
+			.repeat = 1,
+		);
+		skel = cb_refs__open_opts(&opts);
+		if (!ASSERT_OK_PTR(skel, "cb_refs__open_and_load"))
+			return;
+		prog = bpf_object__find_program_by_name(skel->obj, cb_refs_tests[i].prog_name);
+		bpf_program__set_autoload(prog, true);
+		if (!ASSERT_ERR(cb_refs__load(skel), "cb_refs__load"))
+			bpf_prog_test_run_opts(bpf_program__fd(prog), &run_opts);
+		if (!ASSERT_OK_PTR(strstr(log_buf, cb_refs_tests[i].err_msg), "expected error message")) {
+			fprintf(stderr, "Expected: %s\n", cb_refs_tests[i].err_msg);
+			fprintf(stderr, "Verifier: %s\n", log_buf);
+		}
+		cb_refs__destroy(skel);
+	}
+}