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
11 static 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)
24
25 void test_fexit_sleep(void)
26 {
27 struct fexit_sleep_lskel *fexit_skel = NULL;
28 int wstatus, duration = 0;
29 pid_t cpid;
30 char *child_stack = NULL;
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 child_stack = mmap(NULL, STACK_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE |
42 MAP_ANONYMOUS | MAP_STACK, -1, 0);
43 if (!ASSERT_NEQ(child_stack, MAP_FAILED, "mmap"))
44 goto cleanup;
45
46 cpid = clone(do_sleep, child_stack + STACK_SIZE, CLONE_FILES | SIGCHLD, fexit_skel);
47 if (CHECK(cpid == -1, "clone", "%s\n", strerror(errno)))
48 goto cleanup;
49
50 /* wait until first sys_nanosleep ends and second sys_nanosleep starts */
51 while (READ_ONCE(fexit_skel->bss->fentry_cnt) != 2);
52 fexit_cnt = READ_ONCE(fexit_skel->bss->fexit_cnt);
53 if (CHECK(fexit_cnt != 1, "fexit_cnt", "%d", fexit_cnt))
54 goto cleanup;
55
56 /* close progs and detach them. That will trigger two nop5->jmp5 rewrites
57 * in the trampolines to skip nanosleep_fexit prog.
58 * The nanosleep_fentry prog will get detached first.
59 * The nanosleep_fexit prog will get detached second.
60 * Detaching will trigger freeing of both progs JITed images.
61 * There will be two dying bpf_tramp_image-s, but only the initial
62 * bpf_tramp_image (with both _fentry and _fexit progs will be stuck
63 * waiting for percpu_ref_kill to confirm). The other one
64 * will be freed quickly.
65 */
66 close(fexit_skel->progs.nanosleep_fentry.prog_fd);
67 close(fexit_skel->progs.nanosleep_fexit.prog_fd);
68 fexit_sleep_lskel__detach(fexit_skel);
69
70 /* kill the thread to unwind sys_nanosleep stack through the trampoline */
71 kill(cpid, 9);
72
73 if (CHECK(waitpid(cpid, &wstatus, 0) == -1, "waitpid", "%s\n", strerror(errno)))
74 goto cleanup;
75 if (CHECK(WEXITSTATUS(wstatus) != 0, "exitstatus", "failed"))
76 goto cleanup;
77
78 /* The bypassed nanosleep_fexit prog shouldn't have executed.
79 * Unlike progs the maps were not freed and directly accessible.
80 */
81 fexit_cnt = READ_ONCE(fexit_skel->bss->fexit_cnt);
82 if (CHECK(fexit_cnt != 1, "fexit_cnt", "%d", fexit_cnt))
83 goto cleanup;
84
85 cleanup:
86 munmap(child_stack, STACK_SIZE);
87 fexit_sleep_lskel__destroy(fexit_skel);
88 }
89
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