1 /* Check if clone (CLONE_THREAD) does not call exit_group (BZ #21512)
2 Copyright (C) 2017-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
23 #include <sys/syscall.h>
25 #include <sys/types.h>
26 #include <linux/futex.h>
28 #include <stackinfo.h> /* For _STACK_GROWS_{UP,DOWN}. */
29 #include <support/check.h>
30 #include <stdatomic.h>
32 /* Test if clone call with CLONE_THREAD does not call exit_group. The 'f'
33 function returns '1', which will be used by clone thread to call the
34 'exit' syscall directly. If _exit is used instead, exit_group will be
35 used and thus the thread group will finish with return value of '1'
36 (where '2' from main thread is expected. */
44 /* Futex wait for TID argument, similar to pthread_join internal
46 #define wait_tid(ctid_ptr, ctid_val) \
48 __typeof (*(ctid_ptr)) __tid; \
49 /* We need acquire MO here so that we synchronize with the \
50 kernel's store to 0 when the clone terminates. */ \
51 while ((__tid = atomic_load_explicit (ctid_ptr, \
52 memory_order_acquire)) != 0) \
53 futex_wait (ctid_ptr, ctid_val); \
57 futex_wait (int *futexp
, int val
)
60 return syscall (__NR_futex
, futexp
, FUTEX_WAIT
, val
);
62 return syscall (__NR_futex_time64
, futexp
, FUTEX_WAIT
, val
);
69 char st
[1024] __attribute__ ((aligned
));
70 int clone_flags
= CLONE_THREAD
;
71 /* Minimum required flags to used along with CLONE_THREAD. */
72 clone_flags
|= CLONE_VM
| CLONE_SIGHAND
;
73 /* We will used ctid to call on futex to wait for thread exit. */
74 clone_flags
|= CLONE_CHILD_CLEARTID
;
75 /* Initialize with a known value. ctid is set to zero by the kernel after the
76 cloned thread has exited. */
77 #define CTID_INIT_VAL 1
78 pid_t ctid
= CTID_INIT_VAL
;
82 extern int __clone2 (int (*__fn
) (void *__arg
), void *__child_stack_base
,
83 size_t __child_stack_size
, int __flags
,
85 tid
= __clone2 (f
, st
, sizeof (st
), clone_flags
, NULL
, /* ptid */ NULL
,
86 /* tls */ NULL
, &ctid
);
89 tid
= clone (f
, st
+ sizeof (st
), clone_flags
, NULL
, /* ptid */ NULL
,
90 /* tls */ NULL
, &ctid
);
92 tid
= clone (f
, st
, clone_flags
, NULL
, /* ptid */ NULL
, /* tls */ NULL
,
95 #error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
99 FAIL_EXIT1 ("clone failed: %m");
101 wait_tid (&ctid
, CTID_INIT_VAL
);
106 #define EXPECTED_STATUS 2
107 #include <support/test-driver.c>