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-rw-r--r--tools/lib/bpf/libbpf.c18
-rw-r--r--tools/lib/bpf/libbpf.h27
-rw-r--r--tools/testing/selftests/bpf/prog_tests/attach_probe.c80
3 files changed, 116 insertions, 9 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 589085466903..42bdba4efd0c 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -11843,6 +11843,8 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
default:
return libbpf_err_ptr(-EINVAL);
}
+ if (!func_name && legacy)
+ return libbpf_err_ptr(-EOPNOTSUPP);
if (!legacy) {
pfd = perf_event_open_probe(false /* uprobe */, retprobe,
@@ -11862,21 +11864,21 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
offset, -1 /* pid */);
}
if (pfd < 0) {
- err = -errno;
- pr_warn("prog '%s': failed to create %s '%s+0x%zx' perf event: %s\n",
+ err = pfd;
+ pr_warn("prog '%s': failed to create %s '%s%s0x%zx' perf event: %s\n",
prog->name, retprobe ? "kretprobe" : "kprobe",
- func_name, offset,
- errstr(err));
+ func_name ?: "", func_name ? "+" : "",
+ offset, errstr(err));
goto err_out;
}
link = bpf_program__attach_perf_event_opts(prog, pfd, &pe_opts);
err = libbpf_get_error(link);
if (err) {
close(pfd);
- pr_warn("prog '%s': failed to attach to %s '%s+0x%zx': %s\n",
+ pr_warn("prog '%s': failed to attach to %s '%s%s0x%zx': %s\n",
prog->name, retprobe ? "kretprobe" : "kprobe",
- func_name, offset,
- errstr(err));
+ func_name ?: "", func_name ? "+" : "",
+ offset, errstr(err));
goto err_clean_legacy;
}
if (legacy) {
@@ -12852,7 +12854,7 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid,
binary_path, func_offset, pid);
}
if (pfd < 0) {
- err = -errno;
+ err = pfd;
pr_warn("prog '%s': failed to create %s '%s:0x%zx' perf event: %s\n",
prog->name, retprobe ? "uretprobe" : "uprobe",
binary_path, func_offset,
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 0be34852350f..bba4e8464396 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -557,7 +557,7 @@ struct bpf_kprobe_opts {
size_t sz;
/* custom user-provided value fetchable through bpf_get_attach_cookie() */
__u64 bpf_cookie;
- /* function's offset to install kprobe to */
+ /* function offset, or raw address if func_name == NULL */
size_t offset;
/* kprobe is return probe */
bool retprobe;
@@ -565,11 +565,36 @@ struct bpf_kprobe_opts {
enum probe_attach_mode attach_mode;
size_t :0;
};
+
#define bpf_kprobe_opts__last_field attach_mode
+/**
+ * @brief **bpf_program__attach_kprobe()** attaches a BPF program to a
+ * kernel function entry or return.
+ *
+ * @param prog BPF program to attach
+ * @param retprobe Attach to function return
+ * @param func_name Name of the kernel function to attach to
+ * @return Reference to the newly created BPF link; or NULL is returned on
+ * error, error code is stored in errno
+ */
LIBBPF_API struct bpf_link *
bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe,
const char *func_name);
+
+/**
+ * @brief **bpf_program__attach_kprobe_opts()** is just like
+ * bpf_program__attach_kprobe() except with an options struct
+ * for various configurations.
+ *
+ * @param prog BPF program to attach
+ * @param func_name Name of the kernel function to attach to. If NULL,
+ * opts->offset is treated as a raw kernel address. Raw-address attach
+ * is supported with PROBE_ATTACH_MODE_PERF and PROBE_ATTACH_MODE_LINK.
+ * @param opts Options for altering program attachment
+ * @return Reference to the newly created BPF link; or NULL is returned on
+ * error, error code is stored in errno
+ */
LIBBPF_API struct bpf_link *
bpf_program__attach_kprobe_opts(const struct bpf_program *prog,
const char *func_name,
diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
index 38852df70c0d..12a841afda68 100644
--- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
+++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
@@ -123,6 +123,80 @@ cleanup:
test_attach_probe_manual__destroy(skel);
}
+/* manual attach address-based kprobe/kretprobe testings */
+static void test_attach_kprobe_by_addr(enum probe_attach_mode attach_mode)
+{
+ LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
+ struct test_attach_probe_manual *skel;
+ unsigned long func_addr;
+
+ if (!ASSERT_OK(load_kallsyms(), "load_kallsyms"))
+ return;
+
+ func_addr = ksym_get_addr(SYS_NANOSLEEP_KPROBE_NAME);
+ if (!ASSERT_NEQ(func_addr, 0UL, "func_addr"))
+ return;
+
+ skel = test_attach_probe_manual__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_kprobe_manual_open_and_load"))
+ return;
+
+ kprobe_opts.attach_mode = attach_mode;
+ kprobe_opts.retprobe = false;
+ kprobe_opts.offset = func_addr;
+ skel->links.handle_kprobe =
+ bpf_program__attach_kprobe_opts(skel->progs.handle_kprobe,
+ NULL, &kprobe_opts);
+ if (!ASSERT_OK_PTR(skel->links.handle_kprobe, "attach_kprobe_by_addr"))
+ goto cleanup;
+
+ kprobe_opts.retprobe = true;
+ skel->links.handle_kretprobe =
+ bpf_program__attach_kprobe_opts(skel->progs.handle_kretprobe,
+ NULL, &kprobe_opts);
+ if (!ASSERT_OK_PTR(skel->links.handle_kretprobe, "attach_kretprobe_by_addr"))
+ goto cleanup;
+
+ /* trigger & validate kprobe && kretprobe */
+ usleep(1);
+
+ ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
+ ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
+
+cleanup:
+ test_attach_probe_manual__destroy(skel);
+}
+
+/* reject legacy address-based kprobe attach */
+static void test_attach_kprobe_legacy_by_addr_reject(void)
+{
+ LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
+ struct test_attach_probe_manual *skel;
+ unsigned long func_addr;
+
+ if (!ASSERT_OK(load_kallsyms(), "load_kallsyms"))
+ return;
+
+ func_addr = ksym_get_addr(SYS_NANOSLEEP_KPROBE_NAME);
+ if (!ASSERT_NEQ(func_addr, 0UL, "func_addr"))
+ return;
+
+ skel = test_attach_probe_manual__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_kprobe_manual_open_and_load"))
+ return;
+
+ kprobe_opts.attach_mode = PROBE_ATTACH_MODE_LEGACY;
+ kprobe_opts.offset = func_addr;
+ skel->links.handle_kprobe =
+ bpf_program__attach_kprobe_opts(skel->progs.handle_kprobe,
+ NULL, &kprobe_opts);
+ ASSERT_ERR_PTR(skel->links.handle_kprobe, "attach_kprobe_legacy_by_addr");
+ ASSERT_EQ(libbpf_get_error(skel->links.handle_kprobe),
+ -EOPNOTSUPP, "attach_kprobe_legacy_by_addr_err");
+
+ test_attach_probe_manual__destroy(skel);
+}
+
/* attach uprobe/uretprobe long event name testings */
static void test_attach_uprobe_long_event_name(void)
{
@@ -478,6 +552,12 @@ void test_attach_probe(void)
test_attach_probe_manual(PROBE_ATTACH_MODE_PERF);
if (test__start_subtest("manual-link"))
test_attach_probe_manual(PROBE_ATTACH_MODE_LINK);
+ if (test__start_subtest("kprobe-perf-by-addr"))
+ test_attach_kprobe_by_addr(PROBE_ATTACH_MODE_PERF);
+ if (test__start_subtest("kprobe-link-by-addr"))
+ test_attach_kprobe_by_addr(PROBE_ATTACH_MODE_LINK);
+ if (test__start_subtest("kprobe-legacy-by-addr-reject"))
+ test_attach_kprobe_legacy_by_addr_reject();
if (test__start_subtest("auto"))
test_attach_probe_auto(skel);
generated by cgit v1.2.3 (git 2.39.0) at 2026-05-13 20:44:38 +0300