Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759413AbYGQHc2 (ORCPT ); Thu, 17 Jul 2008 03:32:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759324AbYGQHaa (ORCPT ); Thu, 17 Jul 2008 03:30:30 -0400 Received: from mx1.redhat.com ([66.187.233.31]:53576 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758628AbYGQHa1 (ORCPT ); Thu, 17 Jul 2008 03:30:27 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Andrew Morton , Linus Torvalds Cc: Ingo Molnar , linux-kernel@vger.kernel.org X-Fcc: ~/Mail/linus Subject: [PATCH 12/23] tracehook: tracehook_consider_fatal_signal In-Reply-To: Roland McGrath's message of Thursday, 17 July 2008 00:25:41 -0700 <20080717072541.F390E15411D@magilla.localdomain> References: <20080717072541.F390E15411D@magilla.localdomain> X-Shopping-List: (1) Ferocious cow carnations (2) Impractical officious snowbulbs (3) Topical expectorants (4) Laborious prosthetic rice hydrants Message-Id: <20080717073023.4DB3A1541A5@magilla.localdomain> Date: Thu, 17 Jul 2008 00:30:23 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2884 Lines: 75 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 --- include/linux/tracehook.h | 21 +++++++++++++++++++++ kernel/signal.c | 9 +++++---- 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 8cffd34..8b4c15e 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -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 /* */ diff --git a/kernel/signal.c b/kernel/signal.c index f68fb01..860afb8 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -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); } @@ -770,7 +770,8 @@ 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. */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/