Adding tests for checking on recovery after failing to
attach uprobe.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
.../bpf/prog_tests/uprobe_multi_test.c | 118 ++++++++++++++++++
1 file changed, 118 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
index bf6ca8e3eb13..e6255d4df81d 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
@@ -516,6 +516,122 @@ static void test_attach_api_fails(void)
uprobe_multi__destroy(skel);
}
+#ifdef __x86_64__
+noinline void uprobe_multi_error_func(void)
+{
+ /*
+ * If --fcf-protection=branch is enabled the gcc generates endbr as
+ * first instruction, so marking the exact address of int3 with the
+ * symbol to be used in the attach_uprobe_fail_trap test below.
+ */
+ asm volatile (
+ ".globl uprobe_multi_error_func_int3; \n"
+ "uprobe_multi_error_func_int3: \n"
+ "int3 \n"
+ );
+}
+
+/*
+ * Attaching uprobe on uprobe_multi_error_func results in error
+ * because it already starts with int3 instruction.
+ */
+static void attach_uprobe_fail_trap(struct uprobe_multi *skel)
+{
+ LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
+ const char *syms[4] = {
+ "uprobe_multi_func_1",
+ "uprobe_multi_func_2",
+ "uprobe_multi_func_3",
+ "uprobe_multi_error_func_int3",
+ };
+
+ opts.syms = syms;
+ opts.cnt = ARRAY_SIZE(syms);
+
+ skel->links.uprobe = bpf_program__attach_uprobe_multi(skel->progs.uprobe, -1,
+ "/proc/self/exe", NULL, &opts);
+ if (!ASSERT_ERR_PTR(skel->links.uprobe, "bpf_program__attach_uprobe_multi")) {
+ bpf_link__destroy(skel->links.uprobe);
+ skel->links.uprobe = NULL;
+ }
+}
+#else
+static void attach_uprobe_fail_trap(struct uprobe_multi *skel) { }
+#endif
+
+short sema_1 __used, sema_2 __used;
+
+static void attach_uprobe_fail_refctr(struct uprobe_multi *skel)
+{
+ unsigned long *tmp_offsets = NULL, *tmp_ref_ctr_offsets = NULL;
+ unsigned long offsets[3], ref_ctr_offsets[3];
+ LIBBPF_OPTS(bpf_link_create_opts, opts);
+ const char *path = "/proc/self/exe";
+ const char *syms[3] = {
+ "uprobe_multi_func_1",
+ "uprobe_multi_func_2",
+ };
+ const char *sema[3] = {
+ "sema_1",
+ "sema_2",
+ };
+ int prog_fd, link_fd, err;
+
+ prog_fd = bpf_program__fd(skel->progs.uprobe_extra);
+
+ err = elf_resolve_syms_offsets("/proc/self/exe", 2, (const char **) &syms,
+ &tmp_offsets, STT_FUNC);
+ if (!ASSERT_OK(err, "elf_resolve_syms_offsets_func"))
+ return;
+
+ err = elf_resolve_syms_offsets("/proc/self/exe", 2, (const char **) &sema,
+ &tmp_ref_ctr_offsets, STT_OBJECT);
+ if (!ASSERT_OK(err, "elf_resolve_syms_offsets_sema"))
+ goto cleanup;
+
+ /*
+ * We attach to 3 uprobes on 2 functions, so 2 uprobes share single function,
+ * but with different ref_ctr_offset which is not allowed and results in fail.
+ */
+ offsets[0] = tmp_offsets[0]; /* uprobe_multi_func_1 */
+ offsets[1] = tmp_offsets[1]; /* uprobe_multi_func_2 */
+ offsets[2] = tmp_offsets[1]; /* uprobe_multi_func_2 */
+
+ ref_ctr_offsets[0] = tmp_ref_ctr_offsets[0]; /* sema_1 */
+ ref_ctr_offsets[1] = tmp_ref_ctr_offsets[1]; /* sema_2 */
+ ref_ctr_offsets[2] = tmp_ref_ctr_offsets[0]; /* sema_1, error */
+
+ opts.uprobe_multi.path = path;
+ opts.uprobe_multi.offsets = (const unsigned long *) &offsets;
+ opts.uprobe_multi.ref_ctr_offsets = (const unsigned long *) &ref_ctr_offsets;
+ opts.uprobe_multi.cnt = 3;
+
+ link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
+ if (!ASSERT_ERR(link_fd, "link_fd"))
+ close(link_fd);
+
+cleanup:
+ free(tmp_ref_ctr_offsets);
+ free(tmp_offsets);
+}
+
+static void test_attach_uprobe_fails(void)
+{
+ struct uprobe_multi *skel = NULL;
+
+ skel = uprobe_multi__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "uprobe_multi__open_and_load"))
+ return;
+
+ /* attach fails due to adding uprobe on trap instruction, x86_64 only */
+ attach_uprobe_fail_trap(skel);
+
+ /* attach fail due to wrong ref_ctr_offs on one of the uprobes */
+ attach_uprobe_fail_refctr(skel);
+
+ uprobe_multi__destroy(skel);
+}
+
static void __test_link_api(struct child *child)
{
int prog_fd, link1_fd = -1, link2_fd = -1, link3_fd = -1, link4_fd = -1;
@@ -703,4 +819,6 @@ void test_uprobe_multi_test(void)
test_bench_attach_usdt();
if (test__start_subtest("attach_api_fails"))
test_attach_api_fails();
+ if (test__start_subtest("attach_uprobe_fails"))
+ test_attach_uprobe_fails();
}
--
2.45.2
