1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2017 FUJITSU LIMITED. All rights reserved.
4 * Author: Guangwen Feng <[email protected]>
5 */
6
7 /*
8 * This is a regression test for a crash caused by memcg function
9 * reentrant on buggy kernel. When doing rmdir(), a pending signal can
10 * interrupt the execution and lead to cgroup_clear_css_refs()
11 * being entered repeatedly, this results in a BUG_ON().
12 */
13
14 #include <errno.h>
15 #include <unistd.h>
16 #include <stdlib.h>
17 #include <sys/types.h>
18 #include <sys/mount.h>
19 #include "tst_test.h"
20 #include "tst_cgroup.h"
21
22 static volatile int sigcounter;
23 static struct tst_cg_group *test_cg;
24 static pid_t ppid;
25
sighandler(int sig LTP_ATTRIBUTE_UNUSED)26 static void sighandler(int sig LTP_ATTRIBUTE_UNUSED)
27 {
28 sigcounter++;
29 }
30
do_child(void)31 static void do_child(void)
32 {
33 while (getppid() == ppid)
34 SAFE_KILL(ppid, SIGUSR1);
35
36 exit(0);
37 }
38
do_test(void)39 static void do_test(void)
40 {
41 pid_t cpid;
42
43 SAFE_SIGNAL(SIGUSR1, sighandler);
44 ppid = getpid();
45
46 cpid = SAFE_FORK();
47 if (cpid == 0)
48 do_child();
49
50 while (sigcounter < 50000) {
51 test_cg = tst_cg_group_mk(tst_cg, "test");
52
53 if (test_cg)
54 test_cg = tst_cg_group_rm(test_cg);
55 }
56
57 SAFE_KILL(cpid, SIGKILL);
58 SAFE_WAIT(NULL);
59
60 tst_res(TPASS, "Bug not reproduced");
61 }
62
setup(void)63 static void setup(void)
64 {
65 struct tst_cg_opts opts;
66
67 memset(&opts, 0, sizeof(opts));
68
69 tst_cg_require("memory", &opts);
70 tst_cg_init();
71 if (TST_CG_VER(tst_cg, "memory") != TST_CG_V1)
72 SAFE_CG_PRINT(tst_cg, "cgroup.subtree_control", "+memory");
73 }
74
cleanup(void)75 static void cleanup(void)
76 {
77 if (test_cg)
78 test_cg = tst_cg_group_rm(test_cg);
79
80 tst_cg_cleanup();
81 }
82
83 static struct tst_test test = {
84 .needs_root = 1,
85 .forks_child = 1,
86 .setup = setup,
87 .cleanup = cleanup,
88 .test_all = do_test,
89 };
90