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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D91FAC2BA19 for ; Tue, 14 Apr 2020 12:16:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD6AC20732 for ; Tue, 14 Apr 2020 12:16:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439974AbgDNMQ1 (ORCPT ); Tue, 14 Apr 2020 08:16:27 -0400 Received: from foss.arm.com ([217.140.110.172]:54178 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729799AbgDNMQT (ORCPT ); Tue, 14 Apr 2020 08:16:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8E1C11FB; Tue, 14 Apr 2020 05:16:18 -0700 (PDT) Received: from [192.168.0.14] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2AA2C3F6C4; Tue, 14 Apr 2020 05:16:17 -0700 (PDT) Subject: Re: [PATCH] arm64: panic on synchronous external abort in kernel context To: Mark Rutland , Xie XiuQi Cc: catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, tanxiaofei@huawei.com, wangxiongfeng2@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20200410015245.23230-1-xiexiuqi@huawei.com> <20200414105923.GA2486@C02TD0UTHF1T.local> From: James Morse Message-ID: Date: Tue, 14 Apr 2020 13:16:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200414105923.GA2486@C02TD0UTHF1T.local> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Xie, On 14/04/2020 11:59, Mark Rutland wrote: > On Fri, Apr 10, 2020 at 09:52:45AM +0800, Xie XiuQi wrote: >> We should panic even panic_on_oops is not set, when we can't recover >> from synchronous external abort in kernel context. Hmm, fault-from-kernel-context doesn't mean the fault affects the kernel. If the kernel is reading or writing from user-space memory for a syscall, its the user-space memory that is affected. This thread can't make progress, so we kill it. If its a kernel thread or we were in irq context, we panic(). I don't think you really want all faults that happen as a result of a kernel access to be fatal! [...] > What exactly are you trying to catch here? If you are seeing a problem > in practice, can you please share your log from a crash? Yes please! I suspect you want to make memory_failure() smarter about faults that affect the kernel text or data. If so, please do it in memory_failure() where it benefits all architectures, and all methods of reporting errors. (we may need a 'synchronous' hint to memory_failure(), it expects everything to be asynchronous). If its not memory, we should extend the RAS handling to know what this error is, and that it is fatal. (e.g. PE state is infected) Thanks, James 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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 378F3C2BA19 for ; Tue, 14 Apr 2020 12:16:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 00A2920732 for ; Tue, 14 Apr 2020 12:16:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OPVw0p93" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00A2920732 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ggE002XnfQGLr5wbyBKTxY/23esVOKvApTkt7plJfPQ=; b=OPVw0p93YnD4Pp nhItme4b+uZgOy3qtu0Km1uY1awQk54WB+uKHLOgHaoaPVVv2HLTzfoepKBSz2vg9qs0fC1dvQRAV iE7V+qCdqIAx5D1sf3TS3xB4jU707FDMQJC2BX56GmAKFM1aW90XHWMx1hO/tEFwWlfLenWboqQU+ oCjM1KO4SLHGzJN0ERqttFd0eD/9evN1o+whkMtsMq/FUOdeIcoMsLD3+bcDDW79S7QOO/sDxN6XO ir88MMWIC6D42ML/jkUDGW7sQnW6y873KZsM73hCwX1bTibqrfDig85FNYi1E85HABPOPPor98Qsa rexI+5YLf9xwmpeyB99g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOKUJ-0006oG-J9; Tue, 14 Apr 2020 12:16:23 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jOKUH-0006nu-Ch for linux-arm-kernel@lists.infradead.org; Tue, 14 Apr 2020 12:16:22 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8E1C11FB; Tue, 14 Apr 2020 05:16:18 -0700 (PDT) Received: from [192.168.0.14] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2AA2C3F6C4; Tue, 14 Apr 2020 05:16:17 -0700 (PDT) Subject: Re: [PATCH] arm64: panic on synchronous external abort in kernel context To: Mark Rutland , Xie XiuQi References: <20200410015245.23230-1-xiexiuqi@huawei.com> <20200414105923.GA2486@C02TD0UTHF1T.local> From: James Morse Message-ID: Date: Tue, 14 Apr 2020 13:16:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200414105923.GA2486@C02TD0UTHF1T.local> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200414_051621_475585_59FED01C X-CRM114-Status: GOOD ( 13.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, linux-kernel@vger.kernel.org, tanxiaofei@huawei.com, tglx@linutronix.de, will@kernel.org, wangxiongfeng2@huawei.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Xie, On 14/04/2020 11:59, Mark Rutland wrote: > On Fri, Apr 10, 2020 at 09:52:45AM +0800, Xie XiuQi wrote: >> We should panic even panic_on_oops is not set, when we can't recover >> from synchronous external abort in kernel context. Hmm, fault-from-kernel-context doesn't mean the fault affects the kernel. If the kernel is reading or writing from user-space memory for a syscall, its the user-space memory that is affected. This thread can't make progress, so we kill it. If its a kernel thread or we were in irq context, we panic(). I don't think you really want all faults that happen as a result of a kernel access to be fatal! [...] > What exactly are you trying to catch here? If you are seeing a problem > in practice, can you please share your log from a crash? Yes please! I suspect you want to make memory_failure() smarter about faults that affect the kernel text or data. If so, please do it in memory_failure() where it benefits all architectures, and all methods of reporting errors. (we may need a 'synchronous' hint to memory_failure(), it expects everything to be asynchronous). If its not memory, we should extend the RAS handling to know what this error is, and that it is fatal. (e.g. PE state is infected) Thanks, James _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel