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 89542C433F5 for ; Wed, 25 May 2022 14:29:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240572AbiEYO3c (ORCPT ); Wed, 25 May 2022 10:29:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57710 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244859AbiEYO3P (ORCPT ); Wed, 25 May 2022 10:29:15 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 1EA8FA7747 for ; Wed, 25 May 2022 07:29:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1653488953; 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=rJXBSsswS1QbSCIORAlXaRxJTnMr6MqFIgMIGnJ+Qao=; b=HzzBTY80BSnVxYCIWwCbTcsQzuxpAk3xUvMim/xXm2E/+m5ZU2dVxZ6W+iE1LOKrSXfraR /weKm7fYgz5ryMDNlXFdmhGb/EzEUSOrrlnIF8weHckBRmidZL2Tn3mooA5MCClCuSXvyA KdDyCXLzL9OOrshVF5wSBl/xJEiWtT8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-252-YR06shO1OwSFVnlHewrk4w-1; Wed, 25 May 2022 10:29:09 -0400 X-MC-Unique: YR06shO1OwSFVnlHewrk4w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1E95485A5BC; Wed, 25 May 2022 14:29:08 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.193.81]) by smtp.corp.redhat.com (Postfix) with SMTP id 8E4F5C15E71; Wed, 25 May 2022 14:28:47 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 25 May 2022 16:29:07 +0200 (CEST) Date: Wed, 25 May 2022 16:28:46 +0200 From: Oleg Nesterov To: "Eric W. Biederman" Cc: 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, 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 Subject: Re: [PATCH 07/16] signal: Wake up the designated parent Message-ID: <20220525142845.GA2687@redhat.com> References: <871qwq5ucx.fsf_-_@email.froward.int.ebiederm.org> <20220518225355.784371-7-ebiederm@xmission.com> <20220524132553.GD14347@redhat.com> <20220524162808.GF14347@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220524162808.GF14347@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/24, Oleg Nesterov wrote: > > On 05/24, Oleg Nesterov wrote: > > > > I fail to understand this patch... > > > > On 05/18, Eric W. Biederman wrote: > > > > > > Today if a process is ptraced only the ptracer will ever be woken up in > > > wait > > > > and why is this wrong? > > > > > Fixes: 75b95953a569 ("job control: Add @for_ptrace to do_notify_parent_cldstop()") > > > > how does this change fix 75b95953a569? > > OK, I guess you mean the 2nd do_notify_parent_cldstop() in ptrace_stop(), > the problematic case is current->ptrace == T. Right? > > I dislike this patch anyway, but let me think more about it. OK, now that I understand the problem, the patch doesn't look bad to me, although I'd ask to make the changelog more clear. After this change __wake_up_parent() can't accept any "parent" from p->parent thread group, but all callers look fine except ptrace_detach(). Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nts0i-00BQNG-Fe for linux-um@lists.infradead.org; Wed, 25 May 2022 14:29:17 +0000 Date: Wed, 25 May 2022 16:28:46 +0200 From: Oleg Nesterov Subject: Re: [PATCH 07/16] signal: Wake up the designated parent Message-ID: <20220525142845.GA2687@redhat.com> References: <871qwq5ucx.fsf_-_@email.froward.int.ebiederm.org> <20220518225355.784371-7-ebiederm@xmission.com> <20220524132553.GD14347@redhat.com> <20220524162808.GF14347@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220524162808.GF14347@redhat.com> 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: "Eric W. Biederman" Cc: 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, 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 On 05/24, Oleg Nesterov wrote: > > On 05/24, Oleg Nesterov wrote: > > > > I fail to understand this patch... > > > > On 05/18, Eric W. Biederman wrote: > > > > > > Today if a process is ptraced only the ptracer will ever be woken up in > > > wait > > > > and why is this wrong? > > > > > Fixes: 75b95953a569 ("job control: Add @for_ptrace to do_notify_parent_cldstop()") > > > > how does this change fix 75b95953a569? > > OK, I guess you mean the 2nd do_notify_parent_cldstop() in ptrace_stop(), > the problematic case is current->ptrace == T. Right? > > I dislike this patch anyway, but let me think more about it. OK, now that I understand the problem, the patch doesn't look bad to me, although I'd ask to make the changelog more clear. After this change __wake_up_parent() can't accept any "parent" from p->parent thread group, but all callers look fine except ptrace_detach(). Oleg. _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Nesterov Date: Wed, 25 May 2022 14:28:46 +0000 Subject: Re: [PATCH 07/16] signal: Wake up the designated parent Message-Id: <20220525142845.GA2687@redhat.com> List-Id: References: <871qwq5ucx.fsf_-_@email.froward.int.ebiederm.org> <20220518225355.784371-7-ebiederm@xmission.com> <20220524132553.GD14347@redhat.com> <20220524162808.GF14347@redhat.com> In-Reply-To: <20220524162808.GF14347@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Eric W. Biederman" Cc: 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, 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 On 05/24, Oleg Nesterov wrote: > > On 05/24, Oleg Nesterov wrote: > > > > I fail to understand this patch... > > > > On 05/18, Eric W. Biederman wrote: > > > > > > Today if a process is ptraced only the ptracer will ever be woken up in > > > wait > > > > and why is this wrong? > > > > > Fixes: 75b95953a569 ("job control: Add @for_ptrace to do_notify_parent_cldstop()") > > > > how does this change fix 75b95953a569? > > OK, I guess you mean the 2nd do_notify_parent_cldstop() in ptrace_stop(), > the problematic case is current->ptrace = T. Right? > > I dislike this patch anyway, but let me think more about it. OK, now that I understand the problem, the patch doesn't look bad to me, although I'd ask to make the changelog more clear. After this change __wake_up_parent() can't accept any "parent" from p->parent thread group, but all callers look fine except ptrace_detach(). Oleg.