Commit 755e276b authored by Tejun Heo's avatar Tejun Heo Committed by Oleg Nesterov
Browse files

ptrace: ptrace_check_attach(): rename @kill to @ignore_state and add comments 



PTRACE_INTERRUPT is going to be added which should also skip
task_is_traced() check in ptrace_check_attach().  Rename @kill to
@ignore_state and make it bool.  Add function comment while at it.

This patch doesn't introduce any behavior difference.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
parent a8f072c1

include/linux/ptrace.h

+1 −1
Original line number Diff line number Diff line
@@ -105,7 +105,7 @@ extern long arch_ptrace(struct task_struct *child, long request, 
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);

extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);

extern void ptrace_disable(struct task_struct *);

extern int ptrace_check_attach(struct task_struct *task, int kill);

extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);

extern int ptrace_request(struct task_struct *child, long request,

			  unsigned long addr, unsigned long data);

extern void ptrace_notify(int exit_code);

kernel/ptrace.c

+19 −5
Original line number Diff line number Diff line
@@ -97,10 +97,24 @@ void __ptrace_unlink(struct task_struct *child) 
	spin_unlock(&child->sighand->siglock);

}



/*

 * Check that we have indeed attached to the thing..

/**

 * ptrace_check_attach - check whether ptracee is ready for ptrace operation

 * @child: ptracee to check for

 * @ignore_state: don't check whether @child is currently %TASK_TRACED

 *

 * Check whether @child is being ptraced by %current and ready for further

 * ptrace operations.  If @ignore_state is %false, @child also should be in

 * %TASK_TRACED state and on return the child is guaranteed to be traced

 * and not executing.  If @ignore_state is %true, @child can be in any

 * state.

 *

 * CONTEXT:

 * Grabs and releases tasklist_lock and @child->sighand->siglock.

 *

 * RETURNS:

 * 0 on success, -ESRCH if %child is not ready.

 */

int ptrace_check_attach(struct task_struct *child, int kill)

int ptrace_check_attach(struct task_struct *child, bool ignore_state)

{

	int ret = -ESRCH;
@@ -119,13 +133,13 @@ int ptrace_check_attach(struct task_struct *child, int kill) 
		 */

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

		WARN_ON_ONCE(task_is_stopped(child));

		if (task_is_traced(child) || kill)

		if (task_is_traced(child) || ignore_state)

			ret = 0;

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

	}

	read_unlock(&tasklist_lock);



	if (!ret && !kill)

	if (!ret && !ignore_state)

		ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;



	/* All systems go.. */

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