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Commit 445a91d2 authored by Roland McGrath's avatar Roland McGrath Committed by Linus Torvalds
Browse files

tracehook: tracehook_consider_fatal_signal 



This defines tracehook_consider_fatal_signal() has a fine-grained hook for
deciding to skip the special cases for a fatal signal, as ptrace does.
There is no change, only cleanup.

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 35de254d

include/linux/tracehook.h

+21 −0
Original line number Diff line number Diff line
@@ -331,4 +331,25 @@ static inline int tracehook_consider_ignored_signal(struct task_struct *task, 
	return (task_ptrace(task) & PT_PTRACED) != 0;

}



/**

 * tracehook_consider_fatal_signal - suppress special handling of fatal signal

 * @task:		task receiving the signal

 * @sig:		signal number being sent

 * @handler:		%SIG_DFL or %SIG_IGN

 *

 * Return nonzero to prevent special handling of this termination signal.

 * Normally @handler is %SIG_DFL.  It can be %SIG_IGN if @sig is ignored,

 * in which case force_sig() is about to reset it to %SIG_DFL.

 * When this returns zero, this signal might cause a quick termination

 * that does not give the debugger a chance to intercept the signal.

 *

 * Called with or without @task->sighand->siglock held.

 */

static inline int tracehook_consider_fatal_signal(struct task_struct *task,

						  int sig,

						  void __user *handler)

{

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

}



#endif	/* <linux/tracehook.h> */

kernel/signal.c

+5 −4
Original line number Diff line number Diff line
@@ -300,12 +300,12 @@ flush_signal_handlers(struct task_struct *t, int force_default) 


int unhandled_signal(struct task_struct *tsk, int sig)

{

	void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;

	if (is_global_init(tsk))

		return 1;

	if (tsk->ptrace & PT_PTRACED)

	if (handler != SIG_IGN && handler != SIG_DFL)

		return 0;

	return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||

		(tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);

	return !tracehook_consider_fatal_signal(tsk, sig, handler);

}
@@ -761,7 +761,8 @@ static void complete_signal(int sig, struct task_struct *p, int group) 
	if (sig_fatal(p, sig) &&

	    !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&

	    !sigismember(&t->real_blocked, sig) &&

	    (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {

	    (sig == SIGKILL ||

	     !tracehook_consider_fatal_signal(t, sig, SIG_DFL))) {

		/*

		 * This signal will be fatal to the whole group.

		 */