Exemple #1
0
/**
 *	freeze_task - send a freeze request to given task
 *	@p: task to send the request to
 *	@sig_only: if set, the request will only be sent if the task has the
 *		PF_FREEZER_NOSIG flag unset
 *	Return value: 'false', if @sig_only is set and the task has
 *		PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
 *
 *	The freeze request is sent by setting the tasks's TIF_FREEZE flag and
 *	either sending a fake signal to it or waking it up, depending on whether
 *	or not it has PF_FREEZER_NOSIG set.  If @sig_only is set and the task
 *	has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
 *	TIF_FREEZE flag will not be set.
 */
bool freeze_task(struct task_struct *p, bool sig_only)
{
	/*
	 * We first check if the task is freezing and next if it has already
	 * been frozen to avoid the race with frozen_process() which first marks
	 * the task as frozen and next clears its TIF_FREEZE.
	 */
	if (!freezing(p)) {
		rmb();
		if (frozen(p))
			return false;

		if (!sig_only || should_send_signal(p))
			set_freeze_flag(p);
		else
			return false;
	}

	if (should_send_signal(p)) {
		if (!signal_pending(p))
			fake_signal_wake_up(p);
	} else if (sig_only) {
		return false;
	} else {
		wake_up_state(p, TASK_INTERRUPTIBLE);
	}

	return true;
}
Exemple #2
0
static int ptrace_detach(struct task_struct *child, unsigned int data)
{
	bool dead = false;

	if (!valid_signal(data))
		return -EIO;

	/* Architecture-specific hardware disable .. */
	ptrace_disable(child);
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

	write_lock_irq(&tasklist_lock);
	/*
	 * This child can be already killed. Make sure de_thread() or
	 * our sub-thread doing do_wait() didn't do release_task() yet.
	 */
	if (child->ptrace) {
		child->exit_code = data;
		dead = __ptrace_detach(current, child);
		if (!child->exit_state)
			wake_up_state(child, TASK_TRACED | TASK_STOPPED);
	}
	write_unlock_irq(&tasklist_lock);

	if (unlikely(dead))
		release_task(child);

	return 0;
}
Exemple #3
0
/**
 *	freeze_task - send a freeze request to given task
 *	@p: task to send the request to
 *	@sig_only: if set, the request will only be sent if the task has the
 *		PF_FREEZER_NOSIG flag unset
 *	Return value: 'false', if @sig_only is set and the task has
 *		PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
 *
 *	The freeze request is sent by setting the tasks's TIF_FREEZE flag and
 *	either sending a fake signal to it or waking it up, depending on whether
 *	or not it has PF_FREEZER_NOSIG set.  If @sig_only is set and the task
 *	has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
 *	TIF_FREEZE flag will not be set.
 */
bool freeze_task(struct task_struct *p, bool sig_only)
{
	/*
	 * We first check if the task is freezing and next if it has already
	 * been frozen to avoid the race with frozen_process() which first marks
	 * the task as frozen and next clears its TIF_FREEZE.
	 */
	if (!freezing(p)) {
		smp_rmb();
		if (frozen(p))
			return false;

		if (!sig_only || should_send_signal(p))
			set_freeze_flag(p);
		else
			return false;
	}

	if (should_send_signal(p)) {
		fake_signal_wake_up(p);
		/*
		 * fake_signal_wake_up() goes through p's scheduler
		 * lock and guarantees that TASK_STOPPED/TRACED ->
		 * TASK_RUNNING transition can't race with task state
		 * testing in try_to_freeze_tasks().
		 */
	} else if (sig_only) {
		return false;
	} else {
		wake_up_state(p, TASK_INTERRUPTIBLE);
	}

	return true;
}
static int ptrace_resume(struct task_struct *child, long request,
			 unsigned long data)
{
	if (!valid_signal(data))
		return -EIO;

	if (request == PTRACE_SYSCALL)
		set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	else
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

#ifdef TIF_SYSCALL_EMU
	if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
		set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
	else
		clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
#endif

	if (is_singleblock(request)) {
		if (unlikely(!arch_has_block_step()))
			return -EIO;
		user_enable_block_step(child);
	} else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
		if (unlikely(!arch_has_single_step()))
			return -EIO;
		user_enable_single_step(child);
	} else {
		user_disable_single_step(child);
	}

	child->exit_code = data;
	wake_up_state(child, __TASK_TRACED);

	return 0;
}
/**
 * freeze_task - send a freeze request to given task
 * @p: task to send the request to
 *
 * If @p is freezing, the freeze request is sent either by sending a fake
 * signal (if it's not a kernel thread) or waking it up (if it's a kernel
 * thread).
 *
 * RETURNS:
 * %false, if @p is not freezing or already frozen; %true, otherwise
 */
bool freeze_task(struct task_struct *p)
{
	unsigned long flags;

	/*
	 * This check can race with freezer_do_not_count, but worst case that
	 * will result in an extra wakeup being sent to the task.  It does not
	 * race with freezer_count(), the barriers in freezer_count() and
	 * freezer_should_skip() ensure that either freezer_count() sees
	 * freezing == true in try_to_freeze() and freezes, or
	 * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
	 * normally.
	 */
	if (freezer_should_skip(p))
		return false;

	spin_lock_irqsave(&freezer_lock, flags);
	if (!freezing(p) || frozen(p)) {
		spin_unlock_irqrestore(&freezer_lock, flags);
		return false;
	}

	if (!(p->flags & PF_KTHREAD))
		fake_signal_wake_up(p);
	else
		wake_up_state(p, TASK_INTERRUPTIBLE);

	spin_unlock_irqrestore(&freezer_lock, flags);
	return true;
}
Exemple #6
0
bool freeze_task(struct task_struct *p, bool sig_only)
{
	
	if (!freezing(p)) {
		rmb();
		if (frozen(p))
			return false;

		if (!sig_only || should_send_signal(p))
			set_freeze_flag(p);
		else
			return false;
	}

	if (should_send_signal(p)) {
		if (!signal_pending(p))
			fake_signal_wake_up(p);
	} else if (sig_only) {
		return false;
	} else {
		wake_up_state(p, TASK_INTERRUPTIBLE);
	}

	return true;
}
Exemple #7
0
/**
 * freeze_task - send a freeze request to given task
 * @p: task to send the request to
 *
 * If @p is freezing, the freeze request is sent by setting %TIF_FREEZE
 * flag and either sending a fake signal to it or waking it up, depending
 * on whether it has %PF_FREEZER_NOSIG set.
 *
 * RETURNS:
 * %false, if @p is not freezing or already frozen; %true, otherwise
 */
bool freeze_task(struct task_struct *p)
{
	unsigned long flags;

	spin_lock_irqsave(&freezer_lock, flags);
	if (!freezing(p) || frozen(p)) {
		spin_unlock_irqrestore(&freezer_lock, flags);
		return false;
	}

	if (!(p->flags & PF_KTHREAD)) {
		fake_signal_wake_up(p);
		/*
		 * fake_signal_wake_up() goes through p's scheduler
		 * lock and guarantees that TASK_STOPPED/TRACED ->
		 * TASK_RUNNING transition can't race with task state
		 * testing in try_to_freeze_tasks().
		 */
	} else {
		wake_up_state(p, TASK_INTERRUPTIBLE);
	}

	spin_unlock_irqrestore(&freezer_lock, flags);
	return true;
}
static void ptrace_unfreeze_traced(struct task_struct *task)
{
	if (task->state != __TASK_TRACED)
		return;

	WARN_ON(!task->ptrace || task->parent != current);

	spin_lock_irq(&task->sighand->siglock);
	if (__fatal_signal_pending(task))
		wake_up_state(task, __TASK_TRACED);
	else
		task->state = TASK_TRACED;
	spin_unlock_irq(&task->sighand->siglock);
}
static void __kthread_unpark(struct task_struct *k, struct kthread *kthread)
{
	clear_bit(KTHREAD_SHOULD_PARK, &kthread->flags);
	/*
	 * We clear the IS_PARKED bit here as we don't wait
	 * until the task has left the park code. So if we'd
	 * park before that happens we'd see the IS_PARKED bit
	 * which might be about to be cleared.
	 */
	if (test_and_clear_bit(KTHREAD_IS_PARKED, &kthread->flags)) {
		if (test_bit(KTHREAD_IS_PER_CPU, &kthread->flags))
			__kthread_bind(k, kthread->cpu, TASK_PARKED);
		wake_up_state(k, TASK_PARKED);
	}
}
Exemple #10
0
/**
 *	freeze_task - send a freeze request to given task
 *	@p: task to send the request to
 *	@with_mm_only: if set, the request will only be sent if the task has its
 *		own mm
 *	Return value: 0, if @with_mm_only is set and the task has no mm of its
 *		own or the task is frozen, 1, otherwise
 *
 *	The freeze request is sent by seting the tasks's TIF_FREEZE flag and
 *	either sending a fake signal to it or waking it up, depending on whether
 *	or not it has its own mm (ie. it is a user land task).  If @with_mm_only
 *	is set and the task has no mm of its own (ie. it is a kernel thread),
 *	its TIF_FREEZE flag should not be set.
 *
 *	The task_lock() is necessary to prevent races with exit_mm() or
 *	use_mm()/unuse_mm() from occuring.
 */
static int freeze_task(struct task_struct *p, int with_mm_only)
{
	int ret = 1;

	task_lock(p);
	if (freezing(p)) {
		if (has_mm(p)) {
			if (!signal_pending(p))
				fake_signal_wake_up(p, 0);
		} else {
			if (with_mm_only)
				ret = 0;
			else
				wake_up_state(p, TASK_INTERRUPTIBLE);
		}
	} else {
		rmb();
		if (frozen(p)) {
			ret = 0;
		} else {
			if (has_mm(p)) {
				set_freeze_flag(p);
				send_fake_signal(p);
			} else {
				if (with_mm_only) {
					ret = 0;
				} else {
					set_freeze_flag(p);
					wake_up_state(p, TASK_INTERRUPTIBLE);
				}
			}
		}
	}
	task_unlock(p);
	return ret;
}
Exemple #11
0
/**
 * freeze_task - send a freeze request to given task
 * @p: task to send the request to
 *
 * If @p is freezing, the freeze request is sent either by sending a fake
 * signal (if it's not a kernel thread) or waking it up (if it's a kernel
 * thread).
 *
 * RETURNS:
 * %false, if @p is not freezing or already frozen; %true, otherwise
 */
bool freeze_task(struct task_struct *p)
{
	unsigned long flags;

	spin_lock_irqsave(&freezer_lock, flags);
	if (!freezing(p) || frozen(p)) {
		spin_unlock_irqrestore(&freezer_lock, flags);
		return false;
	}

	if (!(p->flags & PF_KTHREAD))
		fake_signal_wake_up(p);
	else
		wake_up_state(p, TASK_INTERRUPTIBLE);

	spin_unlock_irqrestore(&freezer_lock, flags);
	return true;
}
Exemple #12
0
/**
 * freeze_task - send a freeze request to given task
 * @p: task to send the request to
 *
 * If @p is freezing, the freeze request is sent either by sending a fake
 * signal (if it's not a kernel thread) or waking it up (if it's a kernel
 * thread).
 *
 * RETURNS:
 * %false, if @p is not freezing or already frozen; %true, otherwise
 */
bool freeze_task(struct task_struct *p)
{
	unsigned long flags;

	/*
	 * This check can race with freezer_do_not_count, but worst case that
	 * will result in an extra wakeup being sent to the task.  It does not
	 * race with freezer_count(), the barriers in freezer_count() and
	 * freezer_should_skip() ensure that either freezer_count() sees
	 * freezing == true in try_to_freeze() and freezes, or
	 * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
	 * normally.
	 */
	if (freezer_should_skip(p))
		return false;

	spin_lock_irqsave(&freezer_lock, flags);
	if (!freezing(p) || frozen(p)) {
		spin_unlock_irqrestore(&freezer_lock, flags);
		return false;
	}

	if (!(p->flags & PF_KTHREAD)) {
		fake_signal_wake_up(p);
		/*
		 * fake_signal_wake_up() goes through p's scheduler
		 * lock and guarantees that TASK_STOPPED/TRACED ->
		 * TASK_RUNNING transition can't race with task state
		 * testing in try_to_freeze_tasks().
		 */
	} else {
		wake_up_state(p, TASK_INTERRUPTIBLE);
	}

	spin_unlock_irqrestore(&freezer_lock, flags);
	return true;
}