selftests/bpf: Test bpf_map__set_autocreate() and related log fixup logic

Add a subtest that excercises bpf_map__set_autocreate() API and
validates that libbpf properly fixes up BPF verifier log with correct
map information.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220428041523.4089853-5-andrii@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/log_fixup.c b/tools/testing/selftests/bpf/prog_tests/log_fixup.c
index be3a956cb3a55539d4aef546d0a1f56cf936ca08..f4ffdcabf4e48c7d428413400b4e8658f72146ff 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/log_fixup.c
+++ b/tools/testing/selftests/bpf/prog_tests/log_fixup.c
@@ -85,7 +85,6 @@ static void bad_core_relo_subprog(void)
        if (!ASSERT_ERR(err, "load_fail"))
                goto cleanup;
 
-       /* there should be no prog loading log because we specified per-prog log buf */
        ASSERT_HAS_SUBSTR(log_buf,
                          ": <invalid CO-RE relocation>\n"
                          "failed to resolve CO-RE relocation <byte_off> ",
@@ -101,6 +100,40 @@ cleanup:
        test_log_fixup__destroy(skel);
 }
 
+static void missing_map(void)
+{
+       char log_buf[8 * 1024];
+       struct test_log_fixup* skel;
+       int err;
+
+       skel = test_log_fixup__open();
+       if (!ASSERT_OK_PTR(skel, "skel_open"))
+               return;
+
+       bpf_map__set_autocreate(skel->maps.missing_map, false);
+
+       bpf_program__set_autoload(skel->progs.use_missing_map, true);
+       bpf_program__set_log_buf(skel->progs.use_missing_map, log_buf, sizeof(log_buf));
+
+       err = test_log_fixup__load(skel);
+       if (!ASSERT_ERR(err, "load_fail"))
+               goto cleanup;
+
+       ASSERT_TRUE(bpf_map__autocreate(skel->maps.existing_map), "existing_map_autocreate");
+       ASSERT_FALSE(bpf_map__autocreate(skel->maps.missing_map), "missing_map_autocreate");
+
+       ASSERT_HAS_SUBSTR(log_buf,
+                         "8: <invalid BPF map reference>\n"
+                         "BPF map 'missing_map' is referenced but wasn't created\n",
+                         "log_buf");
+
+       if (env.verbosity > VERBOSE_NONE)
+               printf("LOG:   \n=================\n%s=================\n", log_buf);
+
+cleanup:
+       test_log_fixup__destroy(skel);
+}
+
 void test_log_fixup(void)
 {
        if (test__start_subtest("bad_core_relo_trunc_none"))
@@ -111,4 +144,6 @@ void test_log_fixup(void)
                bad_core_relo(250, TRUNC_FULL  /* truncate also libbpf's message patch */);
        if (test__start_subtest("bad_core_relo_subprog"))
                bad_core_relo_subprog();
+       if (test__start_subtest("missing_map"))
+               missing_map();
 }

diff --git a/tools/testing/selftests/bpf/progs/test_log_fixup.c b/tools/testing/selftests/bpf/progs/test_log_fixup.c
index a78980d897b34dd7b6c2e39212786fd91f79d8bb..60450cb0e72ec48b41096a279a1ca2b7bccc5a2e 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_log_fixup.c
+++ b/tools/testing/selftests/bpf/progs/test_log_fixup.c
@@ -35,4 +35,30 @@ int bad_relo_subprog(const void *ctx)
        return bad_subprog() + bpf_core_field_size(t->pid);
 }
 
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __uint(max_entries, 1);
+       __type(key, int);
+       __type(value, int);
+} existing_map SEC(".maps");
+
+struct {
+       __uint(type, BPF_MAP_TYPE_ARRAY);
+       __uint(max_entries, 1);
+       __type(key, int);
+       __type(value, int);
+} missing_map SEC(".maps");
+
+SEC("?raw_tp/sys_enter")
+int use_missing_map(const void *ctx)
+{
+       int zero = 0, *value;
+
+       value = bpf_map_lookup_elem(&existing_map, &zero);
+
+       value = bpf_map_lookup_elem(&missing_map, &zero);
+
+       return value != NULL;
+}
+
 char _license[] SEC("license") = "GPL";