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Commit b787f7ba authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

tracehook: force signal_pending() 



This defines a new hook tracehook_force_sigpending() that lets tracing
code decide to force TIF_SIGPENDING on in recalc_sigpending().

This is not used yet, so it compiles away to nothing for now.  It lays the
groundwork for new tracing code that can interrupt a task synthetically
without actually sending a signal.

Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2b2a1ff6

include/linux/tracehook.h

+14 −0
Original line number Original line Diff line number Diff line
@@ -422,6 +422,20 @@ static inline int tracehook_consider_fatal_signal(struct task_struct *task, 
	return (task_ptrace(task) & PT_PTRACED) != 0;

	return (task_ptrace(task) & PT_PTRACED) != 0;

}

}





/**

 * tracehook_force_sigpending - let tracing force signal_pending(current) on

 *

 * Called when recomputing our signal_pending() flag.  Return nonzero

 * to force the signal_pending() flag on, so that tracehook_get_signal()

 * will be called before the next return to user mode.

 *

 * Called with @current->sighand->siglock held.

 */

static inline int tracehook_force_sigpending(void)

{

	return 0;

}



/**

/**

 * tracehook_get_signal - deliver synthetic signal to traced task

 * tracehook_get_signal - deliver synthetic signal to traced task

 * @task:		@current

 * @task:		@current

kernel/signal.c

+3 −1
Original line number Original line Diff line number Diff line
@@ -134,7 +134,9 @@ void recalc_sigpending_and_wake(struct task_struct *t) 




void recalc_sigpending(void)

void recalc_sigpending(void)

{

{

	if (!recalc_sigpending_tsk(current) && !freezing(current))

	if (unlikely(tracehook_force_sigpending()))

		set_thread_flag(TIF_SIGPENDING);

	else if (!recalc_sigpending_tsk(current) && !freezing(current))

		clear_thread_flag(TIF_SIGPENDING);

		clear_thread_flag(TIF_SIGPENDING);





}

}