[PATCHv3 perf/core 6/6] selftests/bpf: Add kprobe multi write ctx attach test

[Jiri Olsa]

Adding test to check we can't attach kprobe multi program
that writes to the context.

It's x86_64 specific test.

Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 .../bpf/prog_tests/kprobe_multi_test.c        | 27 +++++++++++++++++++
 .../selftests/bpf/progs/kprobe_write_ctx.c    |  7 +++++
 2 files changed, 34 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c 
b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
index e19ef509ebf8..bc52389217e2 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -7,6 +7,7 @@
 #include "kprobe_multi_session.skel.h"
 #include "kprobe_multi_session_cookie.skel.h"
 #include "kprobe_multi_verifier.skel.h"
+#include "kprobe_write_ctx.skel.h"
 #include "bpf/libbpf_internal.h"
 #include "bpf/hashmap.h"
 
@@ -753,6 +754,30 @@ static void test_attach_override(void)
        kprobe_multi_override__destroy(skel);
 }
 
+#ifdef __x86_64__
+static void test_attach_write_ctx(void)
+{
+       struct kprobe_write_ctx *skel = NULL;
+       struct bpf_link *link = NULL;
+
+       skel = kprobe_write_ctx__open_and_load();
+       if (!ASSERT_OK_PTR(skel, "kprobe_write_ctx__open_and_load"))
+               return;
+
+       link = 
bpf_program__attach_kprobe_opts(skel->progs.kprobe_multi_write_ctx,
+                                                    "bpf_fentry_test1", NULL);
+       if (!ASSERT_ERR_PTR(link, "bpf_program__attach_kprobe_opts"))
+               bpf_link__destroy(link);
+
+       kprobe_write_ctx__destroy(skel);
+}
+#else
+static void test_attach_write_ctx(void)
+{
+       test__skip();
+}
+#endif
+
 void serial_test_kprobe_multi_bench_attach(void)
 {
        if (test__start_subtest("kernel"))
@@ -792,5 +817,7 @@ void test_kprobe_multi_test(void)
                test_session_cookie_skel_api();
        if (test__start_subtest("unique_match"))
                test_unique_match();
+       if (test__start_subtest("attach_write_ctx"))
+               test_attach_write_ctx();
        RUN_TESTS(kprobe_multi_verifier);
 }
diff --git a/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c 
b/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c
index 4621a5bef4e2..f77aef0474d3 100644
--- a/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c
+++ b/tools/testing/selftests/bpf/progs/kprobe_write_ctx.c
@@ -12,4 +12,11 @@ int kprobe_write_ctx(struct pt_regs *ctx)
        ctx->ax = 0;
        return 0;
 }
+
+SEC("kprobe.multi")
+int kprobe_multi_write_ctx(struct pt_regs *ctx)
+{
+       ctx->ax = 0;
+       return 0;
+}
 #endif
-- 
2.51.0