From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756046AbZECTA6 (ORCPT ); Sun, 3 May 2009 15:00:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754271AbZECTAs (ORCPT ); Sun, 3 May 2009 15:00:48 -0400 Received: from mx2.redhat.com ([66.187.237.31]:59470 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752279AbZECTAr (ORCPT ); Sun, 3 May 2009 15:00:47 -0400 Date: Sun, 3 May 2009 20:55:45 +0200 From: Oleg Nesterov To: Andrew Morton , Roland McGrath Cc: Jeff Dike , utrace-devel@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] utrace-core-kill-exclude_xtrace-logic Message-ID: <20090503185545.GA17080@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (on top of utrace-core.patch) exclude_utrace() has no callers. exclude_ptrace() is called under tasklist_lock + task_lock() but needs utrace->lock. Remove this logic for now. We will either add utrace-ptrace or rework this mutual exclusion later. Signed-off-by: Oleg Nesterov --- kernel/ptrace.c | 18 +----------------- kernel/utrace.c | 8 -------- 2 files changed, 1 insertion(+), 25 deletions(-) --- PTRACE/kernel/ptrace.c~1_EXCLUDE 2009-05-03 19:28:47.000000000 +0200 +++ PTRACE/kernel/ptrace.c 2009-05-03 19:30:15.000000000 +0200 @@ -16,7 +16,6 @@ #include #include #include -#include #include #include #include @@ -175,14 +174,6 @@ bool ptrace_may_access(struct task_struc return !err; } -/* - * For experimental use of utrace, exclude ptrace on the same task. - */ -static inline bool exclude_ptrace(struct task_struct *task) -{ - return unlikely(!!task_utrace_flags(task)); -} - int ptrace_attach(struct task_struct *task) { int retval; @@ -221,11 +212,6 @@ repeat: goto repeat; } - if (exclude_ptrace(task)) { - retval = -EBUSY; - goto bad; - } - if (!task->mm) goto bad; /* the same process cannot be attached many times */ @@ -602,9 +588,7 @@ int ptrace_traceme(void) */ repeat: task_lock(current); - if (exclude_ptrace(current)) { - ret = -EBUSY; - } else if (!(current->ptrace & PT_PTRACED)) { + if (!(current->ptrace & PT_PTRACED)) { /* * See ptrace_attach() comments about the locking here. */ --- PTRACE/kernel/utrace.c~1_EXCLUDE 2009-04-29 14:26:52.000000000 +0200 +++ PTRACE/kernel/utrace.c 2009-05-03 19:29:56.000000000 +0200 @@ -108,14 +108,6 @@ static struct utrace_engine *matching_en } /* - * For experimental use, utrace attach is mutually exclusive with ptrace. - */ -static inline bool exclude_utrace(struct task_struct *task) -{ - return unlikely(!!task->ptrace); -} - -/* * Called without locks, when we might be the first utrace engine to attach. * If this is a newborn thread and we are not the creator, we have to wait * for it. The creator gets the first chance to attach. The PF_STARTING