mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-27 07:20:11 +00:00
139 lines
4.3 KiB
C
139 lines
4.3 KiB
C
/* Bug 20116: Test rapid creation of detached threads.
|
|
Copyright (C) 2017-2024 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; see the file COPYING.LIB. If
|
|
not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
/* The goal of the test is to trigger a failure if the parent touches
|
|
any part of the thread descriptor after the detached thread has
|
|
exited. We test this by creating many detached threads with large
|
|
stacks. The stacks quickly fill the the stack cache and subsequent
|
|
threads will start to cause the thread stacks to be immediately
|
|
unmapped to satisfy the stack cache max. With the stacks being
|
|
unmapped the parent's read of any part of the thread descriptor will
|
|
trigger a segfault. That segfault is what we are trying to cause,
|
|
since any segfault is a defect in the implementation. */
|
|
|
|
#include <pthread.h>
|
|
#include <stdio.h>
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
#include <stdbool.h>
|
|
#include <sys/resource.h>
|
|
#include <support/xthread.h>
|
|
|
|
/* Number of threads to create. */
|
|
enum { threads_to_create = 100000 };
|
|
|
|
/* Number of threads which should spawn other threads. */
|
|
enum { creator_threads = 2 };
|
|
|
|
/* Counter of threads created so far. This is incremented by all the
|
|
running creator threads. */
|
|
static unsigned threads_created;
|
|
|
|
/* Thread callback which does nothing, so that the thread exits
|
|
immediatedly. */
|
|
static void *
|
|
do_nothing (void *arg)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
/* Attribute indicating that the thread should be created in a detached
|
|
fashion. */
|
|
static pthread_attr_t detached;
|
|
|
|
/* Barrier to synchronize initialization. */
|
|
static pthread_barrier_t barrier;
|
|
|
|
static void *
|
|
creator_thread (void *arg)
|
|
{
|
|
int ret;
|
|
xpthread_barrier_wait (&barrier);
|
|
|
|
while (true)
|
|
{
|
|
pthread_t thr;
|
|
/* Thread creation will fail if the kernel does not free old
|
|
threads quickly enough, so we do not report errors. */
|
|
ret = pthread_create (&thr, &detached, do_nothing, NULL);
|
|
if (ret == 0 && __atomic_add_fetch (&threads_created, 1, __ATOMIC_SEQ_CST)
|
|
>= threads_to_create)
|
|
break;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
/* Limit the size of the process, so that memory allocation will
|
|
fail without impacting the entire system. */
|
|
{
|
|
struct rlimit limit;
|
|
if (getrlimit (RLIMIT_AS, &limit) != 0)
|
|
{
|
|
printf ("FAIL: getrlimit (RLIMIT_AS) failed: %m\n");
|
|
return 1;
|
|
}
|
|
/* This limit, 800MB, is just a heuristic. Any value can be
|
|
picked. */
|
|
long target = 800 * 1024 * 1024;
|
|
if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target)
|
|
{
|
|
limit.rlim_cur = target;
|
|
if (setrlimit (RLIMIT_AS, &limit) != 0)
|
|
{
|
|
printf ("FAIL: setrlimit (RLIMIT_AS) failed: %m\n");
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
xpthread_attr_init (&detached);
|
|
|
|
xpthread_attr_setdetachstate (&detached, PTHREAD_CREATE_DETACHED);
|
|
|
|
/* A large thread stack seems beneficial for reproducing a race
|
|
condition in detached thread creation. The goal is to reach the
|
|
limit of the runtime thread stack cache such that the detached
|
|
thread's stack is unmapped after exit and causes a segfault when
|
|
the parent reads the thread descriptor data stored on the the
|
|
unmapped stack. */
|
|
xpthread_attr_setstacksize (&detached, 16 * 1024 * 1024);
|
|
|
|
xpthread_barrier_init (&barrier, NULL, creator_threads);
|
|
|
|
pthread_t threads[creator_threads];
|
|
|
|
for (int i = 0; i < creator_threads; ++i)
|
|
threads[i] = xpthread_create (NULL, creator_thread, NULL);
|
|
|
|
for (int i = 0; i < creator_threads; ++i)
|
|
xpthread_join (threads[i]);
|
|
|
|
xpthread_attr_destroy (&detached);
|
|
|
|
xpthread_barrier_destroy (&barrier);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define TIMEOUT 100
|
|
#include <support/test-driver.c>
|