Use mmap to create the pthread_internal_t.

Bug: 16847284
Change-Id: Ic8c85f95afac1d8422ecb69674c688d1fecb6a44
This commit is contained in:
Yabin Cui 2014-11-25 14:18:12 -08:00
parent eb3a5e026e
commit cc5f6543e3
4 changed files with 34 additions and 11 deletions

View File

@ -158,9 +158,8 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
// Inform the rest of the C library that at least one thread was created.
__isthreaded = 1;
pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(calloc(sizeof(*thread), 1));
pthread_internal_t* thread = __create_thread_struct();
if (thread == NULL) {
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: couldn't allocate thread");
return EAGAIN;
}
@ -179,7 +178,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
// The caller didn't provide a stack, so allocate one.
thread->attr.stack_base = __create_thread_stack(thread);
if (thread->attr.stack_base == NULL) {
free(thread);
__free_thread_struct(thread);
return EAGAIN;
}
} else {
@ -230,7 +229,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
if (!thread->user_allocated_stack()) {
munmap(thread->attr.stack_base, thread->attr.stack_size);
}
free(thread);
__free_thread_struct(thread);
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: clone failed: %s", strerror(errno));
return clone_errno;
}

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@ -37,6 +37,7 @@
extern "C" __noreturn void _exit_with_stack_teardown(void*, size_t);
extern "C" __noreturn void __exit(int);
extern "C" int __set_tid_address(int*);
extern "C" void __set_tls(void*);
/* CAVEAT: our implementation of pthread_cleanup_push/pop doesn't support C++ exceptions
* and thread cancelation
@ -75,6 +76,9 @@ void pthread_exit(void* return_value) {
// space (see pthread_key_delete).
pthread_key_clean_all();
// Clear tls to prevent further use of __get_tls(), see b/16847284.
__set_tls(NULL);
if (thread->alternate_signal_stack != NULL) {
// Tell the kernel to stop using the alternate signal stack.
stack_t ss;
@ -112,12 +116,6 @@ void pthread_exit(void* return_value) {
}
pthread_mutex_unlock(&g_thread_list_lock);
// Perform a second key cleanup. When using jemalloc, a call to free from
// _pthread_internal_remove_locked causes the memory associated with a key
// to be reallocated.
// TODO: When b/16847284 is fixed this call can be removed.
pthread_key_clean_all();
if (user_allocated_stack) {
// Cleaning up this thread's stack is the creator's responsibility, not ours.
__exit(0);

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@ -94,6 +94,9 @@ struct pthread_internal_t {
char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
};
__LIBC_HIDDEN__ pthread_internal_t* __create_thread_struct();
__LIBC_HIDDEN__ void __free_thread_struct(pthread_internal_t*);
__LIBC_HIDDEN__ int __init_thread(pthread_internal_t* thread, bool add_to_thread_list);
__LIBC_HIDDEN__ void __init_tls(pthread_internal_t* thread);
__LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);

View File

@ -28,15 +28,38 @@
#include "pthread_internal.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include "private/bionic_futex.h"
#include "private/bionic_tls.h"
#include "private/libc_logging.h"
#include "private/ScopedPthreadMutexLocker.h"
pthread_internal_t* g_thread_list = NULL;
pthread_mutex_t g_thread_list_lock = PTHREAD_MUTEX_INITIALIZER;
pthread_internal_t* __create_thread_struct() {
void* result = mmap(NULL, sizeof(pthread_internal_t), PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE, -1, 0);
if (result == MAP_FAILED) {
__libc_format_log(ANDROID_LOG_WARN, "libc",
"__create_thread_struct() failed: %s", strerror(errno));
return NULL;
}
return reinterpret_cast<pthread_internal_t*>(result);
}
void __free_thread_struct(pthread_internal_t* thread) {
int result = munmap(thread, sizeof(pthread_internal_t));
if (result != 0) {
__libc_format_log(ANDROID_LOG_WARN, "libc",
"__free_thread_struct() failed: %s", strerror(errno));
}
}
void _pthread_internal_remove_locked(pthread_internal_t* thread) {
if (thread->next != NULL) {
thread->next->prev = thread->prev;
@ -50,7 +73,7 @@ void _pthread_internal_remove_locked(pthread_internal_t* thread) {
// The main thread is not heap-allocated. See __libc_init_tls for the declaration,
// and __libc_init_common for the point where it's added to the thread list.
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_MAIN_THREAD) == 0) {
free(thread);
__free_thread_struct(thread);
}
}