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tracehook: tracehook_consider_fatal_signal

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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: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Roland McGrath 2008-07-25 19:45:52 -07:00 committed by Linus Torvalds
parent 35de254dc6
commit 445a91d2fe
2 changed files with 26 additions and 4 deletions
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21
include/linux/tracehook.h
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@ -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> */

9
kernel/signal.c
View File

@ -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.
*/