mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-29 16:21:07 +00:00
5cc3385654
Without the bar_ctor_finish barrier, it was possible that thread2
re-locked user_lock before ctor had a chance to lock it. ctor then
blocked in its locking operation, xdlopen from the main thread
did not return, and thread2 was stuck waiting in bar_dtor:
thread 1: started.
thread 2: started.
thread 2: locked user_lock.
constructor started: 0.
thread 1: in ctor: started.
thread 3: started.
thread 3: done.
thread 2: unlocked user_lock.
thread 2: locked user_lock.
Fixes the test in commit 83b5323261
("elf: Avoid deadlock between pthread_create and ctors [BZ #28357]").
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
124 lines
3.4 KiB
C
124 lines
3.4 KiB
C
/* Verify that pthread_create does not deadlock when ctors take locks.
|
|
Copyright (C) 2021 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <stdio.h>
|
|
#include <support/xdlfcn.h>
|
|
#include <support/xthread.h>
|
|
|
|
/*
|
|
Check if ctor and pthread_create deadlocks in
|
|
|
|
thread 1: dlopen -> ctor -> lock(user_lock)
|
|
thread 2: lock(user_lock) -> pthread_create
|
|
|
|
or in
|
|
|
|
thread 1: dlclose -> dtor -> lock(user_lock)
|
|
thread 2: lock(user_lock) -> pthread_create
|
|
*/
|
|
|
|
static pthread_barrier_t bar_ctor;
|
|
static pthread_barrier_t bar_ctor_finish;
|
|
static pthread_barrier_t bar_dtor;
|
|
static pthread_mutex_t user_lock = PTHREAD_MUTEX_INITIALIZER;
|
|
|
|
void
|
|
ctor (void)
|
|
{
|
|
xpthread_barrier_wait (&bar_ctor);
|
|
dprintf (1, "thread 1: in ctor: started.\n");
|
|
xpthread_mutex_lock (&user_lock);
|
|
dprintf (1, "thread 1: in ctor: locked user_lock.\n");
|
|
xpthread_mutex_unlock (&user_lock);
|
|
dprintf (1, "thread 1: in ctor: unlocked user_lock.\n");
|
|
dprintf (1, "thread 1: in ctor: done.\n");
|
|
xpthread_barrier_wait (&bar_ctor_finish);
|
|
}
|
|
|
|
void
|
|
dtor (void)
|
|
{
|
|
xpthread_barrier_wait (&bar_dtor);
|
|
dprintf (1, "thread 1: in dtor: started.\n");
|
|
xpthread_mutex_lock (&user_lock);
|
|
dprintf (1, "thread 1: in dtor: locked user_lock.\n");
|
|
xpthread_mutex_unlock (&user_lock);
|
|
dprintf (1, "thread 1: in dtor: unlocked user_lock.\n");
|
|
dprintf (1, "thread 1: in dtor: done.\n");
|
|
}
|
|
|
|
static void *
|
|
thread3 (void *a)
|
|
{
|
|
dprintf (1, "thread 3: started.\n");
|
|
dprintf (1, "thread 3: done.\n");
|
|
return 0;
|
|
}
|
|
|
|
static void *
|
|
thread2 (void *a)
|
|
{
|
|
pthread_t t3;
|
|
dprintf (1, "thread 2: started.\n");
|
|
|
|
xpthread_mutex_lock (&user_lock);
|
|
dprintf (1, "thread 2: locked user_lock.\n");
|
|
xpthread_barrier_wait (&bar_ctor);
|
|
t3 = xpthread_create (0, thread3, 0);
|
|
xpthread_mutex_unlock (&user_lock);
|
|
dprintf (1, "thread 2: unlocked user_lock.\n");
|
|
xpthread_join (t3);
|
|
xpthread_barrier_wait (&bar_ctor_finish);
|
|
|
|
xpthread_mutex_lock (&user_lock);
|
|
dprintf (1, "thread 2: locked user_lock.\n");
|
|
xpthread_barrier_wait (&bar_dtor);
|
|
t3 = xpthread_create (0, thread3, 0);
|
|
xpthread_mutex_unlock (&user_lock);
|
|
dprintf (1, "thread 2: unlocked user_lock.\n");
|
|
xpthread_join (t3);
|
|
|
|
dprintf (1, "thread 2: done.\n");
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
thread1 (void)
|
|
{
|
|
dprintf (1, "thread 1: started.\n");
|
|
xpthread_barrier_init (&bar_ctor, NULL, 2);
|
|
xpthread_barrier_init (&bar_ctor_finish, NULL, 2);
|
|
xpthread_barrier_init (&bar_dtor, NULL, 2);
|
|
pthread_t t2 = xpthread_create (0, thread2, 0);
|
|
void *p = xdlopen ("tst-create1mod.so", RTLD_NOW | RTLD_GLOBAL);
|
|
dprintf (1, "thread 1: dlopen done.\n");
|
|
xdlclose (p);
|
|
dprintf (1, "thread 1: dlclose done.\n");
|
|
xpthread_join (t2);
|
|
dprintf (1, "thread 1: done.\n");
|
|
}
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
thread1 ();
|
|
return 0;
|
|
}
|
|
|
|
#include <support/test-driver.c>
|