platform_bionic/libc/bionic/fork.cpp
Ryan Prichard 03cef383ba Name stack+tls VMAs with PR_SET_VMA_ANON_NAME
Bionic creates a single thread mapping to hold a thread's stack and static
TLS memory. Use PR_SET_VMA_ANON_NAME to name this region
"stack_and_tls:tid". dumpsys meminfo can report this region as "Stack"
memory.

The main thread's memory is instead named stack_and_tls:main, and the VMA
is renamed to stack_and_tls:main in a post-fork child.

For the main thread, and threads using pthread_attr_setstack, Bionic still
creates the stack_and_tls mapping, but it only has TLS memory in it.

Bug: http://b/134795155
Test: run "dumpsys meminfo" and verify that this CL increases the reported
  stack memory usage from about 4MB to 21MB.
Change-Id: Id1f39ff083329e83426130b4ef94222ffacb90ae
Merged-In: Id1f39ff083329e83426130b4ef94222ffacb90ae
2019-07-23 02:06:51 +00:00

67 lines
2.5 KiB
C++

/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <unistd.h>
#include <android/fdsan.h>
#include "private/bionic_defs.h"
#include "pthread_internal.h"
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int fork() {
__bionic_atfork_run_prepare();
pthread_internal_t* self = __get_thread();
int result = clone(nullptr,
nullptr,
(CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD),
nullptr,
nullptr,
nullptr,
&(self->tid));
if (result == 0) {
// Update the cached pid, since clone() will not set it directly (as
// self->tid is updated by the kernel).
self->set_cached_pid(gettid());
// Disable fdsan post-fork, so we don't falsely trigger on processes that
// fork, close all of their fds blindly, and then exec.
android_fdsan_set_error_level(ANDROID_FDSAN_ERROR_LEVEL_DISABLED);
// Reset the stack_and_tls VMA name so it doesn't end with a tid from the
// parent process.
__set_stack_and_tls_vma_name(true);
__bionic_atfork_run_child();
} else {
__bionic_atfork_run_parent();
}
return result;
}