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Fix pthread_getattr_np, pthread_attr_setguardsize, and pthread_attr_setstacksize.

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pthread_getattr_np was reporting the values supplied to us, not the values we
actually used, which is kinda the whole point of pthread_getattr_np.

pthread_attr_setguardsize and pthread_attr_setstacksize were reporting EINVAL
for any size that wasn't a multiple of the system page size. This is
unnecessary. We can just round like POSIX suggests and glibc already does.

Also improve the error reporting for pthread_create failures.

Change-Id: I7ebc518628a8a1161ec72e111def911d500bba71
This commit is contained in:
Elliott Hughes
2013-07-15 14:51:07 -07:00
parent 59ed029b28
commit b95cf0d23a
3 changed files with 113 additions and 16 deletions
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31
libc/bionic/pthread_create.cpp
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@@ -104,8 +104,8 @@ int _init_thread(pthread_internal_t* thread, bool add_to_thread_list) {
if (sched_setscheduler(thread->tid, thread->attr.sched_policy, &param) == -1) {
// For backwards compatibility reasons, we just warn about failures here.
// error = errno;
const char* msg = "pthread_create sched_setscheduler call failed: %s\n";
__libc_format_log(ANDROID_LOG_WARN, "libc", msg, strerror(errno));
__libc_format_log(ANDROID_LOG_WARN, "libc",
"pthread_create sched_setscheduler call failed: %s", strerror(errno));
}
}
@@ -119,20 +119,27 @@ int _init_thread(pthread_internal_t* thread, bool add_to_thread_list) {
return error;
}
static void* __create_thread_stack(size_t stack_size, size_t guard_size) {
static void* __create_thread_stack(pthread_internal_t* thread) {
ScopedPthreadMutexLocker lock(&gPthreadStackCreationLock);
// Create a new private anonymous map.
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
void* stack = mmap(NULL, stack_size, prot, flags, -1, 0);
void* stack = mmap(NULL, thread->attr.stack_size, prot, flags, -1, 0);
if (stack == MAP_FAILED) {
__libc_format_log(ANDROID_LOG_WARN,
"libc",
"pthread_create failed: couldn't allocate %zd-byte stack: %s",
thread->attr.stack_size, strerror(errno));
return NULL;
}
// Set the guard region at the end of the stack to PROT_NONE.
if (mprotect(stack, guard_size, PROT_NONE) == -1) {
munmap(stack, stack_size);
if (mprotect(stack, thread->attr.guard_size, PROT_NONE) == -1) {
__libc_format_log(ANDROID_LOG_WARN, "libc",
"pthread_create failed: couldn't mprotect PROT_NONE %zd-byte stack guard region: %s",
thread->attr.guard_size, strerror(errno));
munmap(stack, thread->attr.stack_size);
return NULL;
}
@@ -164,15 +171,15 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
attr = NULL; // Prevent misuse below.
}
// Make sure the stack size is PAGE_SIZE aligned.
size_t stack_size = (thread->attr.stack_size + (PAGE_SIZE-1)) & ~(PAGE_SIZE-1);
// Make sure the stack size and guard size are multiples of PAGE_SIZE.
thread->attr.stack_size = (thread->attr.stack_size + (PAGE_SIZE-1)) & ~(PAGE_SIZE-1);
thread->attr.guard_size = (thread->attr.guard_size + (PAGE_SIZE-1)) & ~(PAGE_SIZE-1);
if (thread->attr.stack_base == NULL) {
// The caller didn't provide a stack, so allocate one.
thread->attr.stack_base = __create_thread_stack(stack_size, thread->attr.guard_size);
thread->attr.stack_base = __create_thread_stack(thread);
if (thread->attr.stack_base == NULL) {
free(thread);
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: couldn't allocate %zd-byte stack", stack_size);
return EAGAIN;
}
} else {
@@ -181,7 +188,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
}
// Make room for TLS.
void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
// Create a mutex for the thread in TLS_SLOT_SELF to wait on once it starts so we can keep
// it from doing anything until after we notify the debugger about it
@@ -201,7 +208,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
if (tid < 0) {
int clone_errno = errno;
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_STACK) == 0) {
munmap(thread->attr.stack_base, stack_size);
munmap(thread->attr.stack_base, thread->attr.stack_size);
}
free(thread);
__libc_format_log(ANDROID_LOG_WARN, "libc", "pthread_create failed: clone failed: %s", strerror(errno));