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Commit 321fb561 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Tejun Heo
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ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/ 



After "ptrace: Clean transitions between TASK_STOPPED and TRACED"
d79fdd6d, ptrace_check_attach()
should never see a TASK_STOPPED tracee and s/STOPPED/TRACED/ is
no longer legal. Add the warning.

Note: ptrace_check_attach() can be greatly simplified, in particular
it doesn't need tasklist. But I'd prefer another patch for that.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent ee77f075

kernel/ptrace.c

+3 −5
Original line number Original line Diff line number Diff line
@@ -112,16 +112,14 @@ int ptrace_check_attach(struct task_struct *child, int kill) 
	 */

	 */

	read_lock(&tasklist_lock);

	read_lock(&tasklist_lock);

	if ((child->ptrace & PT_PTRACED) && child->parent == current) {

	if ((child->ptrace & PT_PTRACED) && child->parent == current) {

		ret = 0;

		/*

		/*

		 * child->sighand can't be NULL, release_task()

		 * child->sighand can't be NULL, release_task()

		 * does ptrace_unlink() before __exit_signal().

		 * does ptrace_unlink() before __exit_signal().

		 */

		 */

		spin_lock_irq(&child->sighand->siglock);

		spin_lock_irq(&child->sighand->siglock);

		if (task_is_stopped(child))

		WARN_ON_ONCE(task_is_stopped(child));

			child->state = TASK_TRACED;

		if (task_is_traced(child) || kill)

		else if (!task_is_traced(child) && !kill)

			ret = 0;

			ret = -ESRCH;

		spin_unlock_irq(&child->sighand->siglock);

		spin_unlock_irq(&child->sighand->siglock);

	}

	}

	read_unlock(&tasklist_lock);

	read_unlock(&tasklist_lock);