From mboxrd@z Thu Jan 1 00:00:00 1970 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 40F52C433F5 for ; Thu, 28 Apr 2022 14:58:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348679AbiD1PBZ (ORCPT ); Thu, 28 Apr 2022 11:01:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243847AbiD1PBW (ORCPT ); Thu, 28 Apr 2022 11:01:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D702A5DA29 for ; Thu, 28 Apr 2022 07:58:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651157887; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=MckBjl6pEvKZdqgy2wFZthz2dfKSJ3UYla219JW17Jw=; b=iyVvcK+P+xYwYTLIHDDwkv7sB/bFOp/uhpUG7TdTAoG2DexPmSdKbvKPL8dpKBSAx3/XyA vsAJTUKHKmOM7CXfw3T5XrLz4v4oCB3pLp0OQLG6oNiUbwN4/Udsso6WTPPgvkHQybN3jF CNNvYvPb/6hNBdxHWWzUQshhplOsocc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-157-LcUp97UwMqOoyRBIonnmcQ-1; Thu, 28 Apr 2022 10:57:58 -0400 X-MC-Unique: LcUp97UwMqOoyRBIonnmcQ-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8E7103811F24; Thu, 28 Apr 2022 14:57:57 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.151]) by smtp.corp.redhat.com (Postfix) with SMTP id A59CD407E1C0; Thu, 28 Apr 2022 14:57:52 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 28 Apr 2022 16:57:56 +0200 (CEST) Date: Thu, 28 Apr 2022 16:57:50 +0200 From: Oleg Nesterov To: Peter Zijlstra Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, rjw@rjwysocki.net, 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, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Chris Zankel , Max Filippov , inux-xtensa@linux-xtensa.org, Kees Cook , Jann Horn Subject: Re: [PATCH 7/9] ptrace: Simplify the wait_task_inactive call in ptrace_check_attach Message-ID: <20220428145750.GA15485@redhat.com> References: <878rrrh32q.fsf_-_@email.froward.int.ebiederm.org> <20220426225211.308418-7-ebiederm@xmission.com> <20220427151455.GE17421@redhat.com> <20220428111911.GA3804@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/28, Peter Zijlstra wrote: > > On Thu, Apr 28, 2022 at 01:19:11PM +0200, Oleg Nesterov wrote: > > > That is also the reason I couldn't do wait_task_inactive(task, 0) > > > > Ah, I din't notice this patch uses wait_task_inactive(child, 0), > > I think it should do wait_task_inactive(child, __TASK_TRACED). > > Shouldn't we then switch wait_task_inactive() so have & matching instead > of the current ==. Sorry, I don't understand the context... As long as ptrace_freeze_traced() sets __state == __TASK_TRACED (as it currently does) wait_task_inactive(__TASK_TRACED) is what we need ? After we change it to use JOBCTL_DELAY_WAKEKILL and not abuse __state, ptrace_attach() should use wait_task_inactive(TASK_TRACED), but this depends on what exactly we are going to do... Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nk5an-007Ymb-U1 for linux-um@lists.infradead.org; Thu, 28 Apr 2022 14:58:08 +0000 Date: Thu, 28 Apr 2022 16:57:50 +0200 From: Oleg Nesterov Subject: Re: [PATCH 7/9] ptrace: Simplify the wait_task_inactive call in ptrace_check_attach Message-ID: <20220428145750.GA15485@redhat.com> References: <878rrrh32q.fsf_-_@email.froward.int.ebiederm.org> <20220426225211.308418-7-ebiederm@xmission.com> <20220427151455.GE17421@redhat.com> <20220428111911.GA3804@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: Peter Zijlstra Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, rjw@rjwysocki.net, 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, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Chris Zankel , Max Filippov , inux-xtensa@linux-xtensa.org, Kees Cook , Jann Horn On 04/28, Peter Zijlstra wrote: > > On Thu, Apr 28, 2022 at 01:19:11PM +0200, Oleg Nesterov wrote: > > > That is also the reason I couldn't do wait_task_inactive(task, 0) > > > > Ah, I din't notice this patch uses wait_task_inactive(child, 0), > > I think it should do wait_task_inactive(child, __TASK_TRACED). > > Shouldn't we then switch wait_task_inactive() so have & matching instead > of the current ==. Sorry, I don't understand the context... As long as ptrace_freeze_traced() sets __state == __TASK_TRACED (as it currently does) wait_task_inactive(__TASK_TRACED) is what we need ? After we change it to use JOBCTL_DELAY_WAKEKILL and not abuse __state, ptrace_attach() should use wait_task_inactive(TASK_TRACED), but this depends on what exactly we are going to do... Oleg. _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um