From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752063AbbCNTPP (ORCPT ); Sat, 14 Mar 2015 15:15:15 -0400 Received: from relay6-d.mail.gandi.net ([217.70.183.198]:52083 "EHLO relay6-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249AbbCNTPL (ORCPT ); Sat, 14 Mar 2015 15:15:11 -0400 X-Originating-IP: 50.43.43.179 Date: Sat, 14 Mar 2015 12:15:00 -0700 From: Josh Triplett To: Oleg Nesterov Cc: Al Viro , Andrew Morton , Andy Lutomirski , Ingo Molnar , Kees Cook , "Paul E. McKenney" , "H. Peter Anvin" , Rik van Riel , Thomas Gleixner , Thiago Macieira , Michael Kerrisk , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 6/6] clone4: Introduce new CLONE_FD flag to get task exit notification via fd Message-ID: <20150314191500.GC22130@thin> References: <9c39c576e1d9a9912b4aec54d833a73a84d2f592.1426180120.git.josh@joshtriplett.org> <20150314143558.GB12086@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150314143558.GB12086@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 14, 2015 at 03:35:58PM +0100, Oleg Nesterov wrote: > On 03/12, Josh Triplett wrote: > > > > @@ -598,7 +600,9 @@ static void exit_notify(struct task_struct *tsk, int group_dead) > > if (group_dead) > > kill_orphaned_pgrp(tsk->group_leader, NULL); > > > > - if (unlikely(tsk->ptrace)) { > > + if (tsk->autoreap) { > > + autoreap = true; > > + } else if (unlikely(tsk->ptrace)) { > > int sig = thread_group_leader(tsk) && > > thread_group_empty(tsk) && > > !ptrace_reparented(tsk) ? > > @@ -612,8 +616,10 @@ static void exit_notify(struct task_struct *tsk, int group_dead) > > } > > > > tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE; > > - if (tsk->exit_state == EXIT_DEAD) > > + if (tsk->exit_state == EXIT_DEAD) { > > list_add(&tsk->ptrace_entry, &dead); > > + clonefd_do_notify(tsk); > > + } > > And even ignoring semantics issues, this change looks simply buggy anyway ;) > > How can we do list_add(&tsk->ptrace_entry) if it is traced by _another_ task? > ->ptrace_entry is used by debugger. That list_add was there before; I didn't change that. I just added a second line inside the EXIT_DEAD case, to call clonefd_do_notify (which wakes up potential callers of poll/read). - Josh Triplett From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Triplett Subject: Re: [PATCH 6/6] clone4: Introduce new CLONE_FD flag to get task exit notification via fd Date: Sat, 14 Mar 2015 12:15:00 -0700 Message-ID: <20150314191500.GC22130@thin> References: <9c39c576e1d9a9912b4aec54d833a73a84d2f592.1426180120.git.josh@joshtriplett.org> <20150314143558.GB12086@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Al Viro , Andrew Morton , Andy Lutomirski , Ingo Molnar , Kees Cook , "Paul E. McKenney" , "H. Peter Anvin" , Rik van Riel , Thomas Gleixner , Thiago Macieira , Michael Kerrisk , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org To: Oleg Nesterov Return-path: Content-Disposition: inline In-Reply-To: <20150314143558.GB12086-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Sat, Mar 14, 2015 at 03:35:58PM +0100, Oleg Nesterov wrote: > On 03/12, Josh Triplett wrote: > > > > @@ -598,7 +600,9 @@ static void exit_notify(struct task_struct *tsk, int group_dead) > > if (group_dead) > > kill_orphaned_pgrp(tsk->group_leader, NULL); > > > > - if (unlikely(tsk->ptrace)) { > > + if (tsk->autoreap) { > > + autoreap = true; > > + } else if (unlikely(tsk->ptrace)) { > > int sig = thread_group_leader(tsk) && > > thread_group_empty(tsk) && > > !ptrace_reparented(tsk) ? > > @@ -612,8 +616,10 @@ static void exit_notify(struct task_struct *tsk, int group_dead) > > } > > > > tsk->exit_state = autoreap ? EXIT_DEAD : EXIT_ZOMBIE; > > - if (tsk->exit_state == EXIT_DEAD) > > + if (tsk->exit_state == EXIT_DEAD) { > > list_add(&tsk->ptrace_entry, &dead); > > + clonefd_do_notify(tsk); > > + } > > And even ignoring semantics issues, this change looks simply buggy anyway ;) > > How can we do list_add(&tsk->ptrace_entry) if it is traced by _another_ task? > ->ptrace_entry is used by debugger. That list_add was there before; I didn't change that. I just added a second line inside the EXIT_DEAD case, to call clonefd_do_notify (which wakes up potential callers of poll/read). - Josh Triplett