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

// SPDX-License-Identifier: GPL-2.0

#include <unistd.h>
#include <pthread.h>
#include <test_progs.h>
#include "uprobe_multi.skel.h"
#include "uprobe_multi_bench.skel.h"
#include "uprobe_multi_usdt.skel.h"
#include "uprobe_multi_consumers.skel.h"
#include "uprobe_multi_pid_filter.skel.h"
#include "bpf/libbpf_internal.h"
#include "testing_helpers.h"
#include "../sdt.h"

static char test_data[] = "test_data";

noinline void uprobe_multi_func_1(void)
{
	asm volatile ("");
}

noinline void uprobe_multi_func_2(void)
{
	asm volatile ("");
}

noinline void uprobe_multi_func_3(void)
{
	asm volatile ("");
}

noinline void usdt_trigger(void)
{
	STAP_PROBE(test, pid_filter_usdt);
}

struct child {
	int go[2];
	int c2p[2]; /* child -> parent channel */
	int pid;
	int tid;
	pthread_t thread;
	char stack[65536];
};

static void release_child(struct child *child)
{
	int child_status;

	if (!child)
		return;
	close(child->go[1]);
	close(child->go[0]);
	if (child->thread)
		pthread_join(child->thread, NULL);
	close(child->c2p[0]);
	close(child->c2p[1]);
	if (child->pid > 0)
		waitpid(child->pid, &child_status, 0);
}

static void kick_child(struct child *child)
{
	char c = 1;

	if (child) {
		write(child->go[1], &c, 1);
		release_child(child);
	}
	fflush(NULL);
}

static int child_func(void *arg)
{
	struct child *child = arg;
	int err, c;

	close(child->go[1]);

	/* wait for parent's kick */
	err = read(child->go[0], &c, 1);
	if (err != 1)
		exit(err);

	uprobe_multi_func_1();
	uprobe_multi_func_2();
	uprobe_multi_func_3();
	usdt_trigger();

	exit(errno);
}

static int spawn_child_flag(struct child *child, bool clone_vm)
{
	/* pipe to notify child to execute the trigger functions */
	if (pipe(child->go))
		return -1;

	if (clone_vm) {
		child->pid = child->tid = clone(child_func, child->stack + sizeof(child->stack)/2,
						CLONE_VM|SIGCHLD, child);
	} else {
		child->pid = child->tid = fork();
	}
	if (child->pid < 0) {
		release_child(child);
		errno = EINVAL;
		return -1;
	}

	/* fork-ed child */
	if (!clone_vm && child->pid == 0)
		child_func(child);

	return 0;
}

static int spawn_child(struct child *child)
{
	return spawn_child_flag(child, false);
}

static void *child_thread(void *ctx)
{
	struct child *child = ctx;
	int c = 0, err;

	child->tid = syscall(SYS_gettid);

	/* let parent know we are ready */
	err = write(child->c2p[1], &c, 1);
	if (err != 1)
		pthread_exit(&err);

	/* wait for parent's kick */
	err = read(child->go[0], &c, 1);
	if (err != 1)
		pthread_exit(&err);

	uprobe_multi_func_1();
	uprobe_multi_func_2();
	uprobe_multi_func_3();
	usdt_trigger();

	err = 0;
	pthread_exit(&err);
}

static int spawn_thread(struct child *child)
{
	int c, err;

	/* pipe to notify child to execute the trigger functions */
	if (pipe(child->go))
		return -1;
	/* pipe to notify parent that child thread is ready */
	if (pipe(child->c2p)) {
		close(child->go[0]);
		close(child->go[1]);
		return -1;
	}

	child->pid = getpid();

	err = pthread_create(&child->thread, NULL, child_thread, child);
	if (err) {
		err = -errno;
		close(child->go[0]);
		close(child->go[1]);
		close(child->c2p[0]);
		close(child->c2p[1]);
		errno = -err;
		return -1;
	}

	err = read(child->c2p[0], &c, 1);
	if (!ASSERT_EQ(err, 1, "child_thread_ready"))
		return -1;

	return 0;
}

static void uprobe_multi_test_run(struct uprobe_multi *skel, struct child *child)
{
	skel->bss->uprobe_multi_func_1_addr = (__u64) uprobe_multi_func_1;
	skel->bss->uprobe_multi_func_2_addr = (__u64) uprobe_multi_func_2;
	skel->bss->uprobe_multi_func_3_addr = (__u64) uprobe_multi_func_3;

	skel->bss->user_ptr = test_data;

	/*
	 * Disable pid check in bpf program if we are pid filter test,
	 * because the probe should be executed only by child->pid
	 * passed at the probe attach.
	 */
	skel->bss->pid = child ? 0 : getpid();
	skel->bss->expect_pid = child ? child->pid : 0;

	/* trigger all probes, if we are testing child *process*, just to make
	 * sure that PID filtering doesn't let through activations from wrong
	 * PIDs; when we test child *thread*, we don't want to do this to
	 * avoid double counting number of triggering events
	 */
	if (!child || !child->thread) {
		uprobe_multi_func_1();
		uprobe_multi_func_2();
		uprobe_multi_func_3();
		usdt_trigger();
	}

	if (child)
		kick_child(child);

	/*
	 * There are 2 entry and 2 exit probe called for each uprobe_multi_func_[123]
	 * function and each sleepable probe (6) increments uprobe_multi_sleep_result.
	 */
	ASSERT_EQ(skel->bss->uprobe_multi_func_1_result, 2, "uprobe_multi_func_1_result");
	ASSERT_EQ(skel->bss->uprobe_multi_func_2_result, 2, "uprobe_multi_func_2_result");
	ASSERT_EQ(skel->bss->uprobe_multi_func_3_result, 2, "uprobe_multi_func_3_result");

	ASSERT_EQ(skel->bss->uretprobe_multi_func_1_result, 2, "uretprobe_multi_func_1_result");
	ASSERT_EQ(skel->bss->uretprobe_multi_func_2_result, 2, "uretprobe_multi_func_2_result");
	ASSERT_EQ(skel->bss->uretprobe_multi_func_3_result, 2, "uretprobe_multi_func_3_result");

	ASSERT_EQ(skel->bss->uprobe_multi_sleep_result, 6, "uprobe_multi_sleep_result");

	ASSERT_FALSE(skel->bss->bad_pid_seen, "bad_pid_seen");

	if (child) {
		ASSERT_EQ(skel->bss->child_pid, child->pid, "uprobe_multi_child_pid");
		ASSERT_EQ(skel->bss->child_tid, child->tid, "uprobe_multi_child_tid");
	}
}

static void test_skel_api(void)
{
	struct uprobe_multi *skel = NULL;
	int err;

	skel = uprobe_multi__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi__open_and_load"))
		goto cleanup;

	err = uprobe_multi__attach(skel);
	if (!ASSERT_OK(err, "uprobe_multi__attach"))
		goto cleanup;

	uprobe_multi_test_run(skel, NULL);

cleanup:
	uprobe_multi__destroy(skel);
}

static void
__test_attach_api(const char *binary, const char *pattern, struct bpf_uprobe_multi_opts *opts,
		  struct child *child)
{
	pid_t pid = child ? child->pid : -1;
	struct uprobe_multi *skel = NULL;

	skel = uprobe_multi__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi__open_and_load"))
		goto cleanup;

	opts->retprobe = false;
	skel->links.uprobe = bpf_program__attach_uprobe_multi(skel->progs.uprobe, pid,
							      binary, pattern, opts);
	if (!ASSERT_OK_PTR(skel->links.uprobe, "bpf_program__attach_uprobe_multi"))
		goto cleanup;

	opts->retprobe = true;
	skel->links.uretprobe = bpf_program__attach_uprobe_multi(skel->progs.uretprobe, pid,
								 binary, pattern, opts);
	if (!ASSERT_OK_PTR(skel->links.uretprobe, "bpf_program__attach_uprobe_multi"))
		goto cleanup;

	opts->retprobe = false;
	skel->links.uprobe_sleep = bpf_program__attach_uprobe_multi(skel->progs.uprobe_sleep, pid,
								    binary, pattern, opts);
	if (!ASSERT_OK_PTR(skel->links.uprobe_sleep, "bpf_program__attach_uprobe_multi"))
		goto cleanup;

	opts->retprobe = true;
	skel->links.uretprobe_sleep = bpf_program__attach_uprobe_multi(skel->progs.uretprobe_sleep,
								       pid, binary, pattern, opts);
	if (!ASSERT_OK_PTR(skel->links.uretprobe_sleep, "bpf_program__attach_uprobe_multi"))
		goto cleanup;

	opts->retprobe = false;
	skel->links.uprobe_extra = bpf_program__attach_uprobe_multi(skel->progs.uprobe_extra, -1,
								    binary, pattern, opts);
	if (!ASSERT_OK_PTR(skel->links.uprobe_extra, "bpf_program__attach_uprobe_multi"))
		goto cleanup;

	/* Attach (uprobe-backed) USDTs */
	skel->links.usdt_pid = bpf_program__attach_usdt(skel->progs.usdt_pid, pid, binary,
							"test", "pid_filter_usdt", NULL);
	if (!ASSERT_OK_PTR(skel->links.usdt_pid, "attach_usdt_pid"))
		goto cleanup;

	skel->links.usdt_extra = bpf_program__attach_usdt(skel->progs.usdt_extra, -1, binary,
							  "test", "pid_filter_usdt", NULL);
	if (!ASSERT_OK_PTR(skel->links.usdt_extra, "attach_usdt_extra"))
		goto cleanup;

	uprobe_multi_test_run(skel, child);

	ASSERT_FALSE(skel->bss->bad_pid_seen_usdt, "bad_pid_seen_usdt");
	if (child) {
		ASSERT_EQ(skel->bss->child_pid_usdt, child->pid, "usdt_multi_child_pid");
		ASSERT_EQ(skel->bss->child_tid_usdt, child->tid, "usdt_multi_child_tid");
	}
cleanup:
	uprobe_multi__destroy(skel);
}

static void
test_attach_api(const char *binary, const char *pattern, struct bpf_uprobe_multi_opts *opts)
{
	static struct child child;

	/* no pid filter */
	__test_attach_api(binary, pattern, opts, NULL);

	/* pid filter */
	if (!ASSERT_OK(spawn_child(&child), "spawn_child"))
		return;

	__test_attach_api(binary, pattern, opts, &child);

	/* pid filter (thread) */
	if (!ASSERT_OK(spawn_thread(&child), "spawn_thread"))
		return;

	__test_attach_api(binary, pattern, opts, &child);
}

static void test_attach_api_pattern(void)
{
	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);

	test_attach_api("/proc/self/exe", "uprobe_multi_func_*", &opts);
	test_attach_api("/proc/self/exe", "uprobe_multi_func_?", &opts);
}

static void test_attach_api_syms(void)
{
	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
	const char *syms[3] = {
		"uprobe_multi_func_1",
		"uprobe_multi_func_2",
		"uprobe_multi_func_3",
	};

	opts.syms = syms;
	opts.cnt = ARRAY_SIZE(syms);
	test_attach_api("/proc/self/exe", NULL, &opts);
}

static void test_attach_api_fails(void)
{
	LIBBPF_OPTS(bpf_link_create_opts, opts);
	const char *path = "/proc/self/exe";
	struct uprobe_multi *skel = NULL;
	int prog_fd, link_fd = -1;
	unsigned long offset = 0;

	skel = uprobe_multi__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi__open_and_load"))
		goto cleanup;

	prog_fd = bpf_program__fd(skel->progs.uprobe_extra);

	/* abnormal cnt */
	opts.uprobe_multi.path = path;
	opts.uprobe_multi.offsets = &offset;
	opts.uprobe_multi.cnt = INT_MAX;
	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -E2BIG, "big cnt"))
		goto cleanup;

	/* cnt is 0 */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.offsets = (unsigned long *) &offset,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EINVAL, "cnt_is_zero"))
		goto cleanup;

	/* negative offset */
	offset = -1;
	opts.uprobe_multi.path = path;
	opts.uprobe_multi.offsets = (unsigned long *) &offset;
	opts.uprobe_multi.cnt = 1;

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EINVAL, "offset_is_negative"))
		goto cleanup;

	/* offsets is NULL */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EINVAL, "offsets_is_null"))
		goto cleanup;

	/* wrong offsets pointer */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.offsets = (unsigned long *) 1,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EFAULT, "offsets_is_wrong"))
		goto cleanup;

	/* path is NULL */
	offset = 1;
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EINVAL, "path_is_null"))
		goto cleanup;

	/* wrong path pointer  */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = (const char *) 1,
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EFAULT, "path_is_wrong"))
		goto cleanup;

	/* wrong path type */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = "/",
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EBADF, "path_is_wrong_type"))
		goto cleanup;

	/* wrong cookies pointer */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cookies = (__u64 *) 1ULL,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EFAULT, "cookies_is_wrong"))
		goto cleanup;

	/* wrong ref_ctr_offsets pointer */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cookies = (__u64 *) &offset,
		.uprobe_multi.ref_ctr_offsets = (unsigned long *) 1,
		.uprobe_multi.cnt = 1,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EFAULT, "ref_ctr_offsets_is_wrong"))
		goto cleanup;

	/* wrong flags */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.flags = 1 << 31,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	if (!ASSERT_EQ(link_fd, -EINVAL, "wrong_flags"))
		goto cleanup;

	/* wrong pid */
	LIBBPF_OPTS_RESET(opts,
		.uprobe_multi.path = path,
		.uprobe_multi.offsets = (unsigned long *) &offset,
		.uprobe_multi.cnt = 1,
		.uprobe_multi.pid = -2,
	);

	link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_ERR(link_fd, "link_fd"))
		goto cleanup;
	ASSERT_EQ(link_fd, -EINVAL, "pid_is_wrong");

cleanup:
	if (link_fd >= 0)
		close(link_fd);
	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;
	LIBBPF_OPTS(bpf_link_create_opts, opts);
	const char *path = "/proc/self/exe";
	struct uprobe_multi *skel = NULL;
	unsigned long *offsets = NULL;
	const char *syms[3] = {
		"uprobe_multi_func_1",
		"uprobe_multi_func_2",
		"uprobe_multi_func_3",
	};
	int link_extra_fd = -1;
	int err;

	err = elf_resolve_syms_offsets(path, 3, syms, (unsigned long **) &offsets, STT_FUNC);
	if (!ASSERT_OK(err, "elf_resolve_syms_offsets"))
		return;

	opts.uprobe_multi.path = path;
	opts.uprobe_multi.offsets = offsets;
	opts.uprobe_multi.cnt = ARRAY_SIZE(syms);
	opts.uprobe_multi.pid = child ? child->pid : 0;

	skel = uprobe_multi__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi__open_and_load"))
		goto cleanup;

	opts.kprobe_multi.flags = 0;
	prog_fd = bpf_program__fd(skel->progs.uprobe);
	link1_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_GE(link1_fd, 0, "link1_fd"))
		goto cleanup;

	opts.kprobe_multi.flags = BPF_F_UPROBE_MULTI_RETURN;
	prog_fd = bpf_program__fd(skel->progs.uretprobe);
	link2_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_GE(link2_fd, 0, "link2_fd"))
		goto cleanup;

	opts.kprobe_multi.flags = 0;
	prog_fd = bpf_program__fd(skel->progs.uprobe_sleep);
	link3_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_GE(link3_fd, 0, "link3_fd"))
		goto cleanup;

	opts.kprobe_multi.flags = BPF_F_UPROBE_MULTI_RETURN;
	prog_fd = bpf_program__fd(skel->progs.uretprobe_sleep);
	link4_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_GE(link4_fd, 0, "link4_fd"))
		goto cleanup;

	opts.kprobe_multi.flags = 0;
	opts.uprobe_multi.pid = 0;
	prog_fd = bpf_program__fd(skel->progs.uprobe_extra);
	link_extra_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &opts);
	if (!ASSERT_GE(link_extra_fd, 0, "link_extra_fd"))
		goto cleanup;

	uprobe_multi_test_run(skel, child);

cleanup:
	if (link1_fd >= 0)
		close(link1_fd);
	if (link2_fd >= 0)
		close(link2_fd);
	if (link3_fd >= 0)
		close(link3_fd);
	if (link4_fd >= 0)
		close(link4_fd);
	if (link_extra_fd >= 0)
		close(link_extra_fd);

	uprobe_multi__destroy(skel);
	free(offsets);
}

static void test_link_api(void)
{
	static struct child child;

	/* no pid filter */
	__test_link_api(NULL);

	/* pid filter */
	if (!ASSERT_OK(spawn_child(&child), "spawn_child"))
		return;

	__test_link_api(&child);

	/* pid filter (thread) */
	if (!ASSERT_OK(spawn_thread(&child), "spawn_thread"))
		return;

	__test_link_api(&child);
}

static struct bpf_program *
get_program(struct uprobe_multi_consumers *skel, int prog)
{
	switch (prog) {
	case 0:
		return skel->progs.uprobe_0;
	case 1:
		return skel->progs.uprobe_1;
	case 2:
		return skel->progs.uprobe_2;
	case 3:
		return skel->progs.uprobe_3;
	default:
		ASSERT_FAIL("get_program");
		return NULL;
	}
}

static struct bpf_link **
get_link(struct uprobe_multi_consumers *skel, int link)
{
	switch (link) {
	case 0:
		return &skel->links.uprobe_0;
	case 1:
		return &skel->links.uprobe_1;
	case 2:
		return &skel->links.uprobe_2;
	case 3:
		return &skel->links.uprobe_3;
	default:
		ASSERT_FAIL("get_link");
		return NULL;
	}
}

static int uprobe_attach(struct uprobe_multi_consumers *skel, int idx)
{
	struct bpf_program *prog = get_program(skel, idx);
	struct bpf_link **link = get_link(skel, idx);
	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);

	if (!prog || !link)
		return -1;

	/*
	 * bit/prog: 0,1 uprobe entry
	 * bit/prog: 2,3 uprobe return
	 */
	opts.retprobe = idx == 2 || idx == 3;

	*link = bpf_program__attach_uprobe_multi(prog, 0, "/proc/self/exe",
						"uprobe_consumer_test",
						&opts);
	if (!ASSERT_OK_PTR(*link, "bpf_program__attach_uprobe_multi"))
		return -1;
	return 0;
}

static void uprobe_detach(struct uprobe_multi_consumers *skel, int idx)
{
	struct bpf_link **link = get_link(skel, idx);

	bpf_link__destroy(*link);
	*link = NULL;
}

static bool test_bit(int bit, unsigned long val)
{
	return val & (1 << bit);
}

noinline int
uprobe_consumer_test(struct uprobe_multi_consumers *skel,
		     unsigned long before, unsigned long after)
{
	int idx;

	/* detach uprobe for each unset programs in 'before' state ... */
	for (idx = 0; idx < 4; idx++) {
		if (test_bit(idx, before) && !test_bit(idx, after))
			uprobe_detach(skel, idx);
	}

	/* ... and attach all new programs in 'after' state */
	for (idx = 0; idx < 4; idx++) {
		if (!test_bit(idx, before) && test_bit(idx, after)) {
			if (!ASSERT_OK(uprobe_attach(skel, idx), "uprobe_attach_after"))
				return -1;
		}
	}
	return 0;
}

static void consumer_test(struct uprobe_multi_consumers *skel,
			  unsigned long before, unsigned long after)
{
	int err, idx;

	printf("consumer_test before %lu after %lu\n", before, after);

	/* 'before' is each, we attach uprobe for every set idx */
	for (idx = 0; idx < 4; idx++) {
		if (test_bit(idx, before)) {
			if (!ASSERT_OK(uprobe_attach(skel, idx), "uprobe_attach_before"))
				goto cleanup;
		}
	}

	err = uprobe_consumer_test(skel, before, after);
	if (!ASSERT_EQ(err, 0, "uprobe_consumer_test"))
		goto cleanup;

	for (idx = 0; idx < 4; idx++) {
		const char *fmt = "BUG";
		__u64 val = 0;

		if (idx < 2) {
			/*
			 * uprobe entry
			 *   +1 if define in 'before'
			 */
			if (test_bit(idx, before))
				val++;
			fmt = "prog 0/1: uprobe";
		} else {
			/*
			 * uprobe return is tricky ;-)
			 *
			 * to trigger uretprobe consumer, the uretprobe needs to be installed,
			 * which means one of the 'return' uprobes was alive when probe was hit:
			 *
			 *   idxs: 2/3 uprobe return in 'installed' mask
			 *
			 * in addition if 'after' state removes everything that was installed in
			 * 'before' state, then uprobe kernel object goes away and return uprobe
			 * is not installed and we won't hit it even if it's in 'after' state.
			 */
			unsigned long had_uretprobes  = before & 0b1100; /* is uretprobe installed */
			unsigned long probe_preserved = before & after;  /* did uprobe go away */

			if (had_uretprobes && probe_preserved && test_bit(idx, after))
				val++;
			fmt = "idx 2/3: uretprobe";
		}

		ASSERT_EQ(skel->bss->uprobe_result[idx], val, fmt);
		skel->bss->uprobe_result[idx] = 0;
	}

cleanup:
	for (idx = 0; idx < 4; idx++)
		uprobe_detach(skel, idx);
}

static void test_consumers(void)
{
	struct uprobe_multi_consumers *skel;
	int before, after;

	skel = uprobe_multi_consumers__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi_consumers__open_and_load"))
		return;

	/*
	 * The idea of this test is to try all possible combinations of
	 * uprobes consumers attached on single function.
	 *
	 *  - 2 uprobe entry consumer
	 *  - 2 uprobe exit consumers
	 *
	 * The test uses 4 uprobes attached on single function, but that
	 * translates into single uprobe with 4 consumers in kernel.
	 *
	 * The before/after values present the state of attached consumers
	 * before and after the probed function:
	 *
	 *  bit/prog 0,1 : uprobe entry
	 *  bit/prog 2,3 : uprobe return
	 *
	 * For example for:
	 *
	 *   before = 0b0101
	 *   after  = 0b0110
	 *
	 * it means that before we call 'uprobe_consumer_test' we attach
	 * uprobes defined in 'before' value:
	 *
	 *   - bit/prog 0: uprobe entry
	 *   - bit/prog 2: uprobe return
	 *
	 * uprobe_consumer_test is called and inside it we attach and detach
	 * uprobes based on 'after' value:
	 *
	 *   - bit/prog 0: stays untouched
	 *   - bit/prog 2: uprobe return is detached
	 *
	 * uprobe_consumer_test returns and we check counters values increased
	 * by bpf programs on each uprobe to match the expected count based on
	 * before/after bits.
	 */

	for (before = 0; before < 16; before++) {
		for (after = 0; after < 16; after++)
			consumer_test(skel, before, after);
	}

	uprobe_multi_consumers__destroy(skel);
}

static struct bpf_program *uprobe_multi_program(struct uprobe_multi_pid_filter *skel, int idx)
{
	switch (idx) {
	case 0: return skel->progs.uprobe_multi_0;
	case 1: return skel->progs.uprobe_multi_1;
	case 2: return skel->progs.uprobe_multi_2;
	}
	return NULL;
}

#define TASKS 3

static void run_pid_filter(struct uprobe_multi_pid_filter *skel, bool clone_vm, bool retprobe)
{
	LIBBPF_OPTS(bpf_uprobe_multi_opts, opts, .retprobe = retprobe);
	struct bpf_link *link[TASKS] = {};
	struct child child[TASKS] = {};
	int i;

	memset(skel->bss->test, 0, sizeof(skel->bss->test));

	for (i = 0; i < TASKS; i++) {
		if (!ASSERT_OK(spawn_child_flag(&child[i], clone_vm), "spawn_child"))
			goto cleanup;
		skel->bss->pids[i] = child[i].pid;
	}

	for (i = 0; i < TASKS; i++) {
		link[i] = bpf_program__attach_uprobe_multi(uprobe_multi_program(skel, i),
							   child[i].pid, "/proc/self/exe",
							   "uprobe_multi_func_1", &opts);
		if (!ASSERT_OK_PTR(link[i], "bpf_program__attach_uprobe_multi"))
			goto cleanup;
	}

	for (i = 0; i < TASKS; i++)
		kick_child(&child[i]);

	for (i = 0; i < TASKS; i++) {
		ASSERT_EQ(skel->bss->test[i][0], 1, "pid");
		ASSERT_EQ(skel->bss->test[i][1], 0, "unknown");
	}

cleanup:
	for (i = 0; i < TASKS; i++)
		bpf_link__destroy(link[i]);
	for (i = 0; i < TASKS; i++)
		release_child(&child[i]);
}

static void test_pid_filter_process(bool clone_vm)
{
	struct uprobe_multi_pid_filter *skel;

	skel = uprobe_multi_pid_filter__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi_pid_filter__open_and_load"))
		return;

	run_pid_filter(skel, clone_vm, false);
	run_pid_filter(skel, clone_vm, true);

	uprobe_multi_pid_filter__destroy(skel);
}

static void test_bench_attach_uprobe(void)
{
	long attach_start_ns = 0, attach_end_ns = 0;
	struct uprobe_multi_bench *skel = NULL;
	long detach_start_ns, detach_end_ns;
	double attach_delta, detach_delta;
	int err;

	skel = uprobe_multi_bench__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi_bench__open_and_load"))
		goto cleanup;

	attach_start_ns = get_time_ns();

	err = uprobe_multi_bench__attach(skel);
	if (!ASSERT_OK(err, "uprobe_multi_bench__attach"))
		goto cleanup;

	attach_end_ns = get_time_ns();

	system("./uprobe_multi bench");

	ASSERT_EQ(skel->bss->count, 50000, "uprobes_count");

cleanup:
	detach_start_ns = get_time_ns();
	uprobe_multi_bench__destroy(skel);
	detach_end_ns = get_time_ns();

	attach_delta = (attach_end_ns - attach_start_ns) / 1000000000.0;
	detach_delta = (detach_end_ns - detach_start_ns) / 1000000000.0;

	printf("%s: attached in %7.3lfs\n", __func__, attach_delta);
	printf("%s: detached in %7.3lfs\n", __func__, detach_delta);
}

static void test_bench_attach_usdt(void)
{
	long attach_start_ns = 0, attach_end_ns = 0;
	struct uprobe_multi_usdt *skel = NULL;
	long detach_start_ns, detach_end_ns;
	double attach_delta, detach_delta;

	skel = uprobe_multi_usdt__open_and_load();
	if (!ASSERT_OK_PTR(skel, "uprobe_multi__open"))
		goto cleanup;

	attach_start_ns = get_time_ns();

	skel->links.usdt0 = bpf_program__attach_usdt(skel->progs.usdt0, -1, "./uprobe_multi",
						     "test", "usdt", NULL);
	if (!ASSERT_OK_PTR(skel->links.usdt0, "bpf_program__attach_usdt"))
		goto cleanup;

	attach_end_ns = get_time_ns();

	system("./uprobe_multi usdt");

	ASSERT_EQ(skel->bss->count, 50000, "usdt_count");

cleanup:
	detach_start_ns = get_time_ns();
	uprobe_multi_usdt__destroy(skel);
	detach_end_ns = get_time_ns();

	attach_delta = (attach_end_ns - attach_start_ns) / 1000000000.0;
	detach_delta = (detach_end_ns - detach_start_ns) / 1000000000.0;

	printf("%s: attached in %7.3lfs\n", __func__, attach_delta);
	printf("%s: detached in %7.3lfs\n", __func__, detach_delta);
}

void test_uprobe_multi_test(void)
{
	if (test__start_subtest("skel_api"))
		test_skel_api();
	if (test__start_subtest("attach_api_pattern"))
		test_attach_api_pattern();
	if (test__start_subtest("attach_api_syms"))
		test_attach_api_syms();
	if (test__start_subtest("link_api"))
		test_link_api();
	if (test__start_subtest("bench_uprobe"))
		test_bench_attach_uprobe();
	if (test__start_subtest("bench_usdt"))
		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();
	if (test__start_subtest("consumers"))
		test_consumers();
	if (test__start_subtest("filter_fork"))
		test_pid_filter_process(false);
	if (test__start_subtest("filter_clone_vm"))
		test_pid_filter_process(true);
}