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Commit 910ffdb1 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

ptrace: introduce signal_wake_up_state() and ptrace_signal_wake_up() 



Cleanup and preparation for the next change.

signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.

Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.

This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9a928415

include/linux/sched.h

+10 −1
Original line number Diff line number Diff line
@@ -2714,7 +2714,16 @@ static inline void thread_group_cputime_init(struct signal_struct *sig) 
extern void recalc_sigpending_and_wake(struct task_struct *t);

extern void recalc_sigpending(void);



extern void signal_wake_up(struct task_struct *t, int resume_stopped);

extern void signal_wake_up_state(struct task_struct *t, unsigned int state);



static inline void signal_wake_up(struct task_struct *t, bool resume)

{

	signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);

}

static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)

{

	signal_wake_up_state(t, resume ? __TASK_TRACED : 0);

}



/*

 * Wrappers for p->thread_info->cpu access. No-op on UP.

kernel/ptrace.c

+4 −4
Original line number Diff line number Diff line
@@ -117,7 +117,7 @@ void __ptrace_unlink(struct task_struct *child) 
	 * TASK_KILLABLE sleeps.

	 */

	if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))

		signal_wake_up(child, task_is_traced(child));

		ptrace_signal_wake_up(child, true);



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

}
@@ -317,7 +317,7 @@ static int ptrace_attach(struct task_struct *task, long request, 
	 */

	if (task_is_stopped(task) &&

	    task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))

		signal_wake_up(task, 1);

		signal_wake_up_state(task, __TASK_STOPPED);



	spin_unlock(&task->sighand->siglock);
@@ -737,7 +737,7 @@ int ptrace_request(struct task_struct *child, long request, 
		 * tracee into STOP.

		 */

		if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))

			signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);

			ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);



		unlock_task_sighand(child, &flags);

		ret = 0;
@@ -763,7 +763,7 @@ int ptrace_request(struct task_struct *child, long request, 
			 * start of this trap and now.  Trigger re-trap.

			 */

			if (child->jobctl & JOBCTL_TRAP_NOTIFY)

				signal_wake_up(child, true);

				ptrace_signal_wake_up(child, true);

			ret = 0;

		}

		unlock_task_sighand(child, &flags);

kernel/signal.c

+4 −10
Original line number Diff line number Diff line
@@ -680,23 +680,17 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) 
 * No need to set need_resched since signal event passing

 * goes through ->blocked

 */

void signal_wake_up(struct task_struct *t, int resume)

void signal_wake_up_state(struct task_struct *t, unsigned int state)

{

	unsigned int mask;



	set_tsk_thread_flag(t, TIF_SIGPENDING);



	/*

	 * For SIGKILL, we want to wake it up in the stopped/traced/killable

	 * TASK_WAKEKILL also means wake it up in the stopped/traced/killable

	 * case. We don't check t->state here because there is a race with it

	 * executing another processor and just now entering stopped state.

	 * By using wake_up_state, we ensure the process will wake up and

	 * handle its death signal.

	 */

	mask = TASK_INTERRUPTIBLE;

	if (resume)

		mask |= TASK_WAKEKILL;

	if (!wake_up_state(t, mask))

	if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))

		kick_process(t);

}
@@ -844,7 +838,7 @@ static void ptrace_trap_notify(struct task_struct *t) 
	assert_spin_locked(&t->sighand->siglock);



	task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);

	signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);

	ptrace_signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);

}



/*