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=-6.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 62181C43457 for ; Sat, 10 Oct 2020 22:51:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EB792080C for ; Sat, 10 Oct 2020 22:51:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="b1hW6Up9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731377AbgJJWRP (ORCPT ); Sat, 10 Oct 2020 18:17:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43141 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728877AbgJJSnl (ORCPT ); Sat, 10 Oct 2020 14:43:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602355399; 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=b3T/uhWZZo1nQKpbMvJVb5wVVBmliojws1bKYVeo/nA=; b=b1hW6Up9na9/H5QYsySMZXAmYKOeq5tCcSFnjREqpaz8YLhsNIw/HIZ+B4P766Jdw3ieT7 7bPVnZwK8KfEnv49tjdY4EEheK3GbisdPxH0J81j6avg4FtmbOfU0nCC5hJDDnRNt5kVVG xf28Vh5c9e3l5ZDnePtJts9hYrb7qpc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-339-QYmtt5OlNiau9SIU8B6cBg-1; Sat, 10 Oct 2020 13:55:34 -0400 X-MC-Unique: QYmtt5OlNiau9SIU8B6cBg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B63AF1005E5D; Sat, 10 Oct 2020 17:55:31 +0000 (UTC) Received: from treble (ovpn-112-146.rdu2.redhat.com [10.10.112.146]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5036F60C13; Sat, 10 Oct 2020 17:55:23 +0000 (UTC) Date: Sat, 10 Oct 2020 12:55:20 -0500 From: Josh Poimboeuf To: Russell King - ARM Linux admin Cc: Xiaoming Ni , dima@arista.com, will@kernel.org, akpm@linux-foundation.org, christian.brauner@ubuntu.com, viro@zeniv.linux.org.uk, ldufour@linux.ibm.com, amanieu@gmail.com, walken@google.com, ben.dooks@codethink.co.uk, tglx@linutronix.de, bigeasy@linutronix.de, mingo@kernel.org, vincent.whitchurch@axis.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, wangle6@huawei.com, luohaizheng@huawei.com Subject: Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in backtraces Message-ID: <20201010175520.fczgnp66ey2vghkr@treble> References: <20201009075957.110017-1-nixiaoming@huawei.com> <20201009080849.GM1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201009080849.GM1551@shell.armlinux.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 09, 2020 at 09:08:50AM +0100, Russell King - ARM Linux admin wrote: > On Fri, Oct 09, 2020 at 03:59:57PM +0800, Xiaoming Ni wrote: > > Printing raw pointer values in backtraces has potential security > > implications and are of questionable value anyway. > > > > This patch follows x86 and arm64's lead and removes the "Exception stack:" > > dump from kernel backtraces: > > commit a25ffd3a6302a6 ("arm64: traps: Don't print stack or raw > > PC/LR values in backtraces") > > commit 0ee1dd9f5e7eae ("x86/dumpstack: Remove raw stack dump") > > commit bb5e5ce545f203 ("x86/dumpstack: Remove kernel text > > addresses from stack dump") > > > > Signed-off-by: Xiaoming Ni > > I am really not happy about this - it hurts at least my ability to > debug the kernel when people post oopses to the mailing list. If > people wish to make the kernel harder to debug, and are prepared > to be told "your kernel is undebuggable" then this patch is fine. At least on x86 we've had this for four years now, without any apparent harm to debugability. scripts/faddr2line helps. -- Josh