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 static char child_stack[STACK_SIZE]; 25 26 void 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 80 cleanup: 81 fexit_sleep_lskel__destroy(fexit_skel); 82 } 83