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 8769FC433EF for ; Thu, 5 May 2022 17:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382669AbiEERbi (ORCPT ); Thu, 5 May 2022 13:31:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50792 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349228AbiEERbg (ORCPT ); Thu, 5 May 2022 13:31:36 -0400 Received: from us-smtp-delivery-74.mimecast.com (us-smtp-delivery-74.mimecast.com [170.10.133.74]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9983959940 for ; Thu, 5 May 2022 10:27:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651771675; 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=WF7KSuI261u8vVkwn0kUu26vaIBYgg0I47oTcQGVWZc=; b=eRWnLJXT0qcl4r5gPfP2MLB9ypaFC7MrF3TOCsQ/X3fu6xJRek6pRPZ9nWW1MVJnVD5rpw thAQJ/qazXzQU0WdpCYuFH7nx+WjIgoyWgZprZQgjKbCypK8W0Sz9d+WgZVVO2BUUPmJ+v RyUs0veFEkRIRiQVv0+wHhN/4Mc+P7Y= 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-90-OMBnKkxEPYO6IDkxWB4cIw-1; Thu, 05 May 2022 13:27:52 -0400 X-MC-Unique: OMBnKkxEPYO6IDkxWB4cIw-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 52721398CA60; Thu, 5 May 2022 17:27:51 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.3]) by smtp.corp.redhat.com (Postfix) with SMTP id 46F1B40CF905; Thu, 5 May 2022 17:27:45 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 5 May 2022 19:27:51 +0200 (CEST) Date: Thu, 5 May 2022 19:27:45 +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 Subject: Re: [PATCH v3 08/11] ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs Message-ID: <20220505172744.GA13664@redhat.com> References: <87k0b0apne.fsf_-_@email.froward.int.ebiederm.org> <20220504224058.476193-8-ebiederm@xmission.com> <20220505150158.GB13929@redhat.com> <87a6bv7v49.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87a6bv7v49.fsf@email.froward.int.ebiederm.org> 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 05/05, Eric W. Biederman wrote: > > And yes that WARN_ON_ONCE can trigger on PREEMPT_RT but that is just > because PREMPT_RT is currently broken with respect to ptrace. Which > makes a WARN_ON_ONCE appropriate. Yes agreed. In this case WARN_ON_ONCE() can help a user to understand that a failure was caused by the kernel problem which we need to fix anyway. Oleg. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-74.mimecast.com ([170.10.133.74]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nmfGg-00H2KU-WD for linux-um@lists.infradead.org; Thu, 05 May 2022 17:28:00 +0000 Date: Thu, 5 May 2022 19:27:45 +0200 From: Oleg Nesterov Subject: Re: [PATCH v3 08/11] ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs Message-ID: <20220505172744.GA13664@redhat.com> References: <87k0b0apne.fsf_-_@email.froward.int.ebiederm.org> <20220504224058.476193-8-ebiederm@xmission.com> <20220505150158.GB13929@redhat.com> <87a6bv7v49.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87a6bv7v49.fsf@email.froward.int.ebiederm.org> 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 On 05/05, Eric W. Biederman wrote: > > And yes that WARN_ON_ONCE can trigger on PREEMPT_RT but that is just > because PREMPT_RT is currently broken with respect to ptrace. Which > makes a WARN_ON_ONCE appropriate. Yes agreed. In this case WARN_ON_ONCE() can help a user to understand that a failure was caused by the kernel problem which we need to fix anyway. 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: Thu, 05 May 2022 17:27:45 +0000 Subject: Re: [PATCH v3 08/11] ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs Message-Id: <20220505172744.GA13664@redhat.com> List-Id: References: <87k0b0apne.fsf_-_@email.froward.int.ebiederm.org> <20220504224058.476193-8-ebiederm@xmission.com> <20220505150158.GB13929@redhat.com> <87a6bv7v49.fsf@email.froward.int.ebiederm.org> In-Reply-To: <87a6bv7v49.fsf@email.froward.int.ebiederm.org> 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 On 05/05, Eric W. Biederman wrote: > > And yes that WARN_ON_ONCE can trigger on PREEMPT_RT but that is just > because PREMPT_RT is currently broken with respect to ptrace. Which > makes a WARN_ON_ONCE appropriate. Yes agreed. In this case WARN_ON_ONCE() can help a user to understand that a failure was caused by the kernel problem which we need to fix anyway. Oleg.