1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3#define _GNU_SOURCE
4#include <sched.h>
5#include <test_progs.h>
6#include <time.h>
7#include <sys/mman.h>
8#include <sys/syscall.h>
9#include "fexit_sleep.lskel.h"
10
11static int do_sleep(void *skel)
12{
13	struct fexit_sleep_lskel *fexit_skel = skel;
14	struct timespec ts1 = { .tv_nsec = 1 };
15	struct timespec ts2 = { .tv_sec = 10 };
16
17	fexit_skel->bss->pid = getpid();
18	(void)syscall(__NR_nanosleep, &ts1, NULL);
19	(void)syscall(__NR_nanosleep, &ts2, NULL);
20	return 0;
21}
22
23#define STACK_SIZE (1024 * 1024)
24static char child_stack[STACK_SIZE];
25
26void test_fexit_sleep(void)
27{
28	struct fexit_sleep_lskel *fexit_skel = NULL;
29	int wstatus, duration = 0;
30	pid_t cpid;
31	int err, fexit_cnt;
32
33	fexit_skel = fexit_sleep_lskel__open_and_load();
34	if (CHECK(!fexit_skel, "fexit_skel_load", "fexit skeleton failed\n"))
35		goto cleanup;
36
37	err = fexit_sleep_lskel__attach(fexit_skel);
38	if (CHECK(err, "fexit_attach", "fexit attach failed: %d\n", err))
39		goto cleanup;
40
41	cpid = clone(do_sleep, child_stack + STACK_SIZE, CLONE_FILES | SIGCHLD, fexit_skel);
42	if (CHECK(cpid == -1, "clone", "%s\n", strerror(errno)))
43		goto cleanup;
44
45	/* wait until first sys_nanosleep ends and second sys_nanosleep starts */
46	while (READ_ONCE(fexit_skel->bss->fentry_cnt) != 2);
47	fexit_cnt = READ_ONCE(fexit_skel->bss->fexit_cnt);
48	if (CHECK(fexit_cnt != 1, "fexit_cnt", "%d", fexit_cnt))
49		goto cleanup;
50
51	/* close progs and detach them. That will trigger two nop5->jmp5 rewrites
52	 * in the trampolines to skip nanosleep_fexit prog.
53	 * The nanosleep_fentry prog will get detached first.
54	 * The nanosleep_fexit prog will get detached second.
55	 * Detaching will trigger freeing of both progs JITed images.
56	 * There will be two dying bpf_tramp_image-s, but only the initial
57	 * bpf_tramp_image (with both _fentry and _fexit progs will be stuck
58	 * waiting for percpu_ref_kill to confirm). The other one
59	 * will be freed quickly.
60	 */
61	close(fexit_skel->progs.nanosleep_fentry.prog_fd);
62	close(fexit_skel->progs.nanosleep_fexit.prog_fd);
63	fexit_sleep_lskel__detach(fexit_skel);
64
65	/* kill the thread to unwind sys_nanosleep stack through the trampoline */
66	kill(cpid, 9);
67
68	if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", "%s\n", strerror(errno)))
69		goto cleanup;
70	if (CHECK(WEXITSTATUS(wstatus) != 0, "exitstatus", "failed"))
71		goto cleanup;
72
73	/* The bypassed nanosleep_fexit prog shouldn't have executed.
74	 * Unlike progs the maps were not freed and directly accessible.
75	 */
76	fexit_cnt = READ_ONCE(fexit_skel->bss->fexit_cnt);
77	if (CHECK(fexit_cnt != 1, "fexit_cnt", "%d", fexit_cnt))
78		goto cleanup;
79
80cleanup:
81	fexit_sleep_lskel__destroy(fexit_skel);
82}
83