Commit c9e208fa authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add stacktrace ips test for kprobe_multi/kretprobe_multi 



Adding test that attaches kprobe/kretprobe multi and verifies the
ORC stacktrace matches expected functions.

Adding bpf_testmod_stacktrace_test function to bpf_testmod kernel
module which is called through several functions so we get reliable
call path for stacktrace.

The test is only for ORC unwinder to keep it simple.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20251104215405.168643-4-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 20a0bc10

tools/testing/selftests/bpf/prog_tests/stacktrace_ips.c

0 → 100644
+104 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <test_progs.h>

#include "stacktrace_ips.skel.h"



#ifdef __x86_64__

static int check_stacktrace_ips(int fd, __u32 key, int cnt, ...)

{

	__u64 ips[PERF_MAX_STACK_DEPTH];

	struct ksyms *ksyms = NULL;

	int i, err = 0;

	va_list args;



	/* sorted by addr */

	ksyms = load_kallsyms_local();

	if (!ASSERT_OK_PTR(ksyms, "load_kallsyms_local"))

		return -1;



	/* unlikely, but... */

	if (!ASSERT_LT(cnt, PERF_MAX_STACK_DEPTH, "check_max"))

		return -1;



	err = bpf_map_lookup_elem(fd, &key, ips);

	if (err)

		goto out;



	/*

	 * Compare all symbols provided via arguments with stacktrace ips,

	 * and their related symbol addresses.t

	 */

	va_start(args, cnt);



	for (i = 0; i < cnt; i++) {

		unsigned long val;

		struct ksym *ksym;



		val = va_arg(args, unsigned long);

		ksym = ksym_search_local(ksyms, ips[i]);

		if (!ASSERT_OK_PTR(ksym, "ksym_search_local"))

			break;

		ASSERT_EQ(ksym->addr, val, "stack_cmp");

	}



	va_end(args);



out:

	free_kallsyms_local(ksyms);

	return err;

}



static void test_stacktrace_ips_kprobe_multi(bool retprobe)

{

	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts,

		.retprobe = retprobe

	);

	LIBBPF_OPTS(bpf_test_run_opts, topts);

	struct stacktrace_ips *skel;



	skel = stacktrace_ips__open_and_load();

	if (!ASSERT_OK_PTR(skel, "stacktrace_ips__open_and_load"))

		return;



	if (!skel->kconfig->CONFIG_UNWINDER_ORC) {

		test__skip();

		goto cleanup;

	}



	skel->links.kprobe_multi_test = bpf_program__attach_kprobe_multi_opts(

							skel->progs.kprobe_multi_test,

							"bpf_testmod_stacktrace_test", &opts);

	if (!ASSERT_OK_PTR(skel->links.kprobe_multi_test, "bpf_program__attach_kprobe_multi_opts"))

		goto cleanup;



	trigger_module_test_read(1);



	load_kallsyms();



	check_stacktrace_ips(bpf_map__fd(skel->maps.stackmap), skel->bss->stack_key, 4,

			     ksym_get_addr("bpf_testmod_stacktrace_test_3"),

			     ksym_get_addr("bpf_testmod_stacktrace_test_2"),

			     ksym_get_addr("bpf_testmod_stacktrace_test_1"),

			     ksym_get_addr("bpf_testmod_test_read"));



cleanup:

	stacktrace_ips__destroy(skel);

}



static void __test_stacktrace_ips(void)

{

	if (test__start_subtest("kprobe_multi"))

		test_stacktrace_ips_kprobe_multi(false);

	if (test__start_subtest("kretprobe_multi"))

		test_stacktrace_ips_kprobe_multi(true);

}

#else

static void __test_stacktrace_ips(void)

{

	test__skip();

}

#endif



void test_stacktrace_ips(void)

{

	__test_stacktrace_ips();

}

tools/testing/selftests/bpf/progs/stacktrace_ips.c

0 → 100644
+41 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

// Copyright (c) 2018 Facebook



#include <vmlinux.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



#ifndef PERF_MAX_STACK_DEPTH

#define PERF_MAX_STACK_DEPTH         127

#endif



typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];



struct {

	__uint(type, BPF_MAP_TYPE_STACK_TRACE);

	__uint(max_entries, 16384);

	__type(key, __u32);

	__type(value, stack_trace_t);

} stackmap SEC(".maps");



extern bool CONFIG_UNWINDER_ORC __kconfig __weak;



/*

 * This function is here to have CONFIG_UNWINDER_ORC

 * used and added to object BTF.

 */

int unused(void)

{

	return CONFIG_UNWINDER_ORC ? 0 : 1;

}



__u32 stack_key;



SEC("kprobe.multi")

int kprobe_multi_test(struct pt_regs *ctx)

{

	stack_key = bpf_get_stackid(ctx, &stackmap, 0);

	return 0;

}



char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_kmods/bpf_testmod.c

+26 −0
Original line number Diff line number Diff line
@@ -417,6 +417,30 @@ noinline int bpf_testmod_fentry_test11(u64 a, void *b, short c, int d, 
	return a + (long)b + c + d + (long)e + f + g + h + i + j + k;

}



noinline void bpf_testmod_stacktrace_test(void)

{

	/* used for stacktrace test as attach function */

	asm volatile ("");

}



noinline void bpf_testmod_stacktrace_test_3(void)

{

	bpf_testmod_stacktrace_test();

	asm volatile ("");

}



noinline void bpf_testmod_stacktrace_test_2(void)

{

	bpf_testmod_stacktrace_test_3();

	asm volatile ("");

}



noinline void bpf_testmod_stacktrace_test_1(void)

{

	bpf_testmod_stacktrace_test_2();

	asm volatile ("");

}



int bpf_testmod_fentry_ok;



noinline ssize_t
@@ -497,6 +521,8 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj, 
			21, 22, 23, 24, 25, 26) != 231)

		goto out;



	bpf_testmod_stacktrace_test_1();



	bpf_testmod_fentry_ok = 1;

out:

	return -EIO; /* always fail */