selftests/bpf: Add link_info test for uprobe_multi link

Adding fill_link_info test for uprobe_multi link.

Setting up uprobes with bogus ref_ctr_offsets and cookie values
to test all the bpf_link_info::uprobe_multi fields.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20231125193130.834322-6-jolsa@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
index 9294cb8d7743e07a2a20106da98f382323a9b612..d4b1901f7879af31e37daeed22db2e064a28f09f 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -7,6 +7,7 @@
 #include <test_progs.h>
 #include "trace_helpers.h"
 #include "test_fill_link_info.skel.h"
+#include "bpf/libbpf_internal.h"
 
 #define TP_CAT "sched"
 #define TP_NAME "sched_switch"
@@ -300,6 +301,196 @@ static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
        bpf_link__destroy(link);
 }
 
+#define SEC(name) __attribute__((section(name), used))
+
+static short uprobe_link_info_sema_1 SEC(".probes");
+static short uprobe_link_info_sema_2 SEC(".probes");
+static short uprobe_link_info_sema_3 SEC(".probes");
+
+noinline void uprobe_link_info_func_1(void)
+{
+       asm volatile ("");
+       uprobe_link_info_sema_1++;
+}
+
+noinline void uprobe_link_info_func_2(void)
+{
+       asm volatile ("");
+       uprobe_link_info_sema_2++;
+}
+
+noinline void uprobe_link_info_func_3(void)
+{
+       asm volatile ("");
+       uprobe_link_info_sema_3++;
+}
+
+static int
+verify_umulti_link_info(int fd, bool retprobe, __u64 *offsets,
+                       __u64 *cookies, __u64 *ref_ctr_offsets)
+{
+       char path[PATH_MAX], path_buf[PATH_MAX];
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       __u64 ref_ctr_offsets_buf[3];
+       __u64 offsets_buf[3];
+       __u64 cookies_buf[3];
+       int i, err, bit;
+       __u32 count = 0;
+
+       memset(path, 0, sizeof(path));
+       err = readlink("/proc/self/exe", path, sizeof(path));
+       if (!ASSERT_NEQ(err, -1, "readlink"))
+               return -1;
+
+       for (bit = 0; bit < 8; bit++) {
+               memset(&info, 0, sizeof(info));
+               info.uprobe_multi.path = ptr_to_u64(path_buf);
+               info.uprobe_multi.path_size = sizeof(path_buf);
+               info.uprobe_multi.count = count;
+
+               if (bit & 0x1)
+                       info.uprobe_multi.offsets = ptr_to_u64(offsets_buf);
+               if (bit & 0x2)
+                       info.uprobe_multi.cookies = ptr_to_u64(cookies_buf);
+               if (bit & 0x4)
+                       info.uprobe_multi.ref_ctr_offsets = ptr_to_u64(ref_ctr_offsets_buf);
+
+               err = bpf_link_get_info_by_fd(fd, &info, &len);
+               if (!ASSERT_OK(err, "bpf_link_get_info_by_fd"))
+                       return -1;
+
+               if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_UPROBE_MULTI, "info.type"))
+                       return -1;
+
+               ASSERT_EQ(info.uprobe_multi.pid, getpid(), "info.uprobe_multi.pid");
+               ASSERT_EQ(info.uprobe_multi.count, 3, "info.uprobe_multi.count");
+               ASSERT_EQ(info.uprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN,
+                         retprobe, "info.uprobe_multi.flags.retprobe");
+               ASSERT_EQ(info.uprobe_multi.path_size, strlen(path) + 1, "info.uprobe_multi.path_size");
+               ASSERT_STREQ(path_buf, path, "info.uprobe_multi.path");
+
+               for (i = 0; i < info.uprobe_multi.count; i++) {
+                       if (info.uprobe_multi.offsets)
+                               ASSERT_EQ(offsets_buf[i], offsets[i], "info.uprobe_multi.offsets");
+                       if (info.uprobe_multi.cookies)
+                               ASSERT_EQ(cookies_buf[i], cookies[i], "info.uprobe_multi.cookies");
+                       if (info.uprobe_multi.ref_ctr_offsets) {
+                               ASSERT_EQ(ref_ctr_offsets_buf[i], ref_ctr_offsets[i],
+                                         "info.uprobe_multi.ref_ctr_offsets");
+                       }
+               }
+               count = count ?: info.uprobe_multi.count;
+       }
+
+       return 0;
+}
+
+static void verify_umulti_invalid_user_buffer(int fd)
+{
+       struct bpf_link_info info;
+       __u32 len = sizeof(info);
+       __u64 buf[3];
+       int err;
+
+       /* upath_size defined, not path */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.path_size = 3;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "failed_upath_size");
+
+       /* path defined, but small */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.path = ptr_to_u64(buf);
+       info.uprobe_multi.path_size = 3;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_LT(err, 0, "failed_upath_small");
+
+       /* path has wrong pointer */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.path_size = PATH_MAX;
+       info.uprobe_multi.path = 123;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EFAULT, "failed_bad_path_ptr");
+
+       /* count zero, with offsets */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.offsets = ptr_to_u64(buf);
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EINVAL, "failed_count");
+
+       /* offsets not big enough */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.offsets = ptr_to_u64(buf);
+       info.uprobe_multi.count = 2;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -ENOSPC, "failed_small_count");
+
+       /* offsets has wrong pointer */
+       memset(&info, 0, sizeof(info));
+       info.uprobe_multi.offsets = 123;
+       info.uprobe_multi.count = 3;
+       err = bpf_link_get_info_by_fd(fd, &info, &len);
+       ASSERT_EQ(err, -EFAULT, "failed_wrong_offsets");
+}
+
+static void test_uprobe_multi_fill_link_info(struct test_fill_link_info *skel,
+                                            bool retprobe, bool invalid)
+{
+       LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
+               .retprobe = retprobe,
+       );
+       const char *syms[3] = {
+               "uprobe_link_info_func_1",
+               "uprobe_link_info_func_2",
+               "uprobe_link_info_func_3",
+       };
+       __u64 cookies[3] = {
+               0xdead,
+               0xbeef,
+               0xcafe,
+       };
+       const char *sema[3] = {
+               "uprobe_link_info_sema_1",
+               "uprobe_link_info_sema_2",
+               "uprobe_link_info_sema_3",
+       };
+       __u64 *offsets = NULL, *ref_ctr_offsets;
+       struct bpf_link *link;
+       int link_fd, err;
+
+       err = elf_resolve_syms_offsets("/proc/self/exe", 3, sema,
+                                      (unsigned long **) &ref_ctr_offsets, STT_OBJECT);
+       if (!ASSERT_OK(err, "elf_resolve_syms_offsets_object"))
+               return;
+
+       err = elf_resolve_syms_offsets("/proc/self/exe", 3, syms,
+                                      (unsigned long **) &offsets, STT_FUNC);
+       if (!ASSERT_OK(err, "elf_resolve_syms_offsets_func"))
+               goto out;
+
+       opts.syms = syms;
+       opts.cookies = &cookies[0];
+       opts.ref_ctr_offsets = (unsigned long *) &ref_ctr_offsets[0];
+       opts.cnt = ARRAY_SIZE(syms);
+
+       link = bpf_program__attach_uprobe_multi(skel->progs.umulti_run, 0,
+                                               "/proc/self/exe", NULL, &opts);
+       if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
+               goto out;
+
+       link_fd = bpf_link__fd(link);
+       if (invalid)
+               verify_umulti_invalid_user_buffer(link_fd);
+       else
+               verify_umulti_link_info(link_fd, retprobe, offsets, cookies, ref_ctr_offsets);
+
+       bpf_link__destroy(link);
+out:
+       free(ref_ctr_offsets);
+       free(offsets);
+}
+
 void test_fill_link_info(void)
 {
        struct test_fill_link_info *skel;
@@ -339,6 +530,13 @@ void test_fill_link_info(void)
        if (test__start_subtest("kprobe_multi_invalid_ubuff"))
                test_kprobe_multi_fill_link_info(skel, true, true);
 
+       if (test__start_subtest("uprobe_multi_link_info"))
+               test_uprobe_multi_fill_link_info(skel, false, false);
+       if (test__start_subtest("uretprobe_multi_link_info"))
+               test_uprobe_multi_fill_link_info(skel, true, false);
+       if (test__start_subtest("uprobe_multi_invalid"))
+               test_uprobe_multi_fill_link_info(skel, false, true);
+
 cleanup:
        test_fill_link_info__destroy(skel);
 }

diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
index 564f402d56fef7770ba886cffe3bd348c374d05c..69509f8bb680f838262bea2b24ba6e9a1f023a00 100644 (file)
--- a/tools/testing/selftests/bpf/progs/test_fill_link_info.c
+++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
@@ -39,4 +39,10 @@ int BPF_PROG(kmulti_run)
        return 0;
 }
 
+SEC("uprobe.multi")
+int BPF_PROG(umulti_run)
+{
+       return 0;
+}
+
 char _license[] SEC("license") = "GPL";