3e2d2936b0
Expecting the memory in a forked child process to be sane wrt threading is a bad idea. An example of a problem is when the parent process has the malloc lock and a child process is forked. The malloc lock in the child will appear locked by a thread that doesn't exist. This change aims to make bionic more compatible with glibc by reseting the malloc lock in the child forked process, as well as holding it during the fork. This is a feature in dlmalloc 2.8.6 called LOCK_AT_FORK. In general this feature isn't necessary as a forked process will then exec. Some bad applications rely on being able to use features like malloc before the exec and having multiple threads running in the parent program. This isn't a problem with glibc and this patch makes it not a problem for bionic. Unfortunately for use in bionic, LOCK_AT_FORK has an issue as internally it uses pthread_atfork that in bionic uses malloc. This leads to the LOCK_AT_FORK initialization deadlocking with pthread_atfork's call to malloc due to the malloc lock. This change moves the pthread_atfork logic in LOCK_AT_FORK to be called without the malloc lock held. Change-Id: Id68175a564a6abb936ee4488b44d9479f7311f69
34 lines
1 KiB
C
34 lines
1 KiB
C
/*
|
|
* Copyright (C) 2012 The Android Open Source Project
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#ifndef LIBC_BIONIC_DLMALLOC_H_
|
|
#define LIBC_BIONIC_DLMALLOC_H_
|
|
|
|
/* Configure dlmalloc. */
|
|
#define HAVE_GETPAGESIZE 1
|
|
#define MALLOC_INSPECT_ALL 1
|
|
#define MSPACES 0
|
|
#define REALLOC_ZERO_BYTES_FREES 1
|
|
#define USE_DL_PREFIX 1
|
|
#define USE_LOCKS 1
|
|
#define LOCK_AT_FORK 1
|
|
#define USE_RECURSIVE_LOCK 0
|
|
#define USE_SPIN_LOCKS 0
|
|
|
|
/* Include the proper definitions. */
|
|
#include "../upstream-dlmalloc/malloc.h"
|
|
|
|
#endif // LIBC_BIONIC_DLMALLOC_H_
|