From patchwork Wed May 18 22:53:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 12854229 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4200C433EF for ; Wed, 18 May 2022 22:55:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230415AbiERWy7 (ORCPT ); Wed, 18 May 2022 18:54:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230314AbiERWyq (ORCPT ); Wed, 18 May 2022 18:54:46 -0400 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF9C52265E4; Wed, 18 May 2022 15:54:44 -0700 (PDT) Received: from in01.mta.xmission.com ([166.70.13.51]:54828) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nrSZ1-001T58-Fx; Wed, 18 May 2022 16:54:43 -0600 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:38724 helo=localhost.localdomain) by in01.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nrSZ0-002Z0O-DQ; Wed, 18 May 2022 16:54:43 -0600 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: rjw@rjwysocki.net, Oleg Nesterov , mingo@kernel.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, mgorman@suse.de, bigeasy@linutronix.de, Will Deacon , tj@kernel.org, linux-pm@vger.kernel.org, Peter Zijlstra , Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Chris Zankel , Max Filippov , linux-xtensa@linux-xtensa.org, Kees Cook , Jann Horn , linux-ia64@vger.kernel.org, Robert OCallahan , Kyle Huey , Richard Henderson , Ivan Kokshaysky , Matt Turner , Jason Wessel , Daniel Thompson , Douglas Anderson , Douglas Miller , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , "Eric W. Biederman" Date: Wed, 18 May 2022 17:53:44 -0500 Message-Id: <20220518225355.784371-5-ebiederm@xmission.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <871qwq5ucx.fsf_-_@email.froward.int.ebiederm.org> References: <871qwq5ucx.fsf_-_@email.froward.int.ebiederm.org> MIME-Version: 1.0 X-XM-SPF: eid=1nrSZ0-002Z0O-DQ;;;mid=<20220518225355.784371-5-ebiederm@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=softfail X-XM-AID: U2FsdGVkX19bmUj59Un5KGL2qB5b8KKLljIsiq43aWI= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 05/16] ptrace: Remove dead code from __ptrace_detach X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Ever since commit 28d838cc4dfe ("Fix ptrace self-attach rule") it has been impossible to attach another thread in the same thread group. Remove the code from __ptrace_detach that was trying to support detaching from a thread in the same thread group. The code is dead and I can not make sense of what it is trying to do. Signed-off-by: "Eric W. Biederman" --- kernel/ptrace.c | 24 +++--------------------- 1 file changed, 3 insertions(+), 21 deletions(-) diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 328a34a99124..ca0e47691229 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -526,19 +526,6 @@ static int ptrace_traceme(void) return ret; } -/* - * Called with irqs disabled, returns true if childs should reap themselves. - */ -static int ignoring_children(struct sighand_struct *sigh) -{ - int ret; - spin_lock(&sigh->siglock); - ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || - (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); - spin_unlock(&sigh->siglock); - return ret; -} - /* * Called with tasklist_lock held for writing. * Unlink a traced task, and clean it up if it was a traced zombie. @@ -565,14 +552,9 @@ static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) dead = !thread_group_leader(p); - if (!dead && thread_group_empty(p)) { - if (!same_thread_group(p->real_parent, tracer)) - dead = do_notify_parent(p, p->exit_signal); - else if (ignoring_children(tracer->sighand)) { - __wake_up_parent(p, tracer); - dead = true; - } - } + if (!dead && thread_group_empty(p)) + dead = do_notify_parent(p, p->exit_signal); + /* Mark it as in the process of being reaped. */ if (dead) p->exit_state = EXIT_DEAD;