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=-0.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED autolearn=ham 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 2BF20C43142 for ; Fri, 22 Jun 2018 16:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E135245BB for ; Fri, 22 Jun 2018 16:21:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="e2jfAp6U" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E135245BB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934191AbeFVQVi (ORCPT ); Fri, 22 Jun 2018 12:21:38 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:54742 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934049AbeFVQVg (ORCPT ); Fri, 22 Jun 2018 12:21:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=DxGmMZZRMPH6CM8VicfGWQPSlifXQVyBx3Yhs8sqx18=; b=e2jfAp6UGkmfShbSZ9n4s+5bB r7mYBKvWBcZwk8WV/vyb4XuUsooaZ/wP0X+Wx6ZMEV/xJ74gLs71+vPc0xlkDDCdwutWTgQ7U0xTG CsKUvonM8gkSqN04A5i9QBeq53wC3tZKKMoI20kWyb9MuBj1l3qOR1MvZkmPQCrJ/2W6AnQWCHsSz NoQKmhLDvJfhYPHJvgRkiEJAFUmDR9DZqrFGKHc7/ZMfm5K8pU/pqo+WYMdC/jypdmmFjs06IqEDg cd64A2E4ulcuXa0iIxhf0R/daY2nD0jeI1W+++O6iBXYL8fDaVcZCgzV12a0UOu0rdnSajiiJ21JI vwQPwc6Eg==; Received: from static-50-53-52-16.bvtn.or.frontiernet.net ([50.53.52.16] helo=midway.dunlab) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fWOoY-0005cB-9V; Fri, 22 Jun 2018 16:21:34 +0000 Subject: Re: [PATCH v9 4/4] vsprintf: Add command line option debug_boot_weak_hash To: "Tobin C. Harding" , Theodore Ts'o Cc: Linus Torvalds , Steven Rostedt , Kees Cook , Anna-Maria Gleixner , Andrew Morton , Greg Kroah-Hartman , Arnd Bergmann , Andy Shevchenko , linux-kernel@vger.kernel.org References: <20180621231534.32278-1-me@tobin.cc> <20180621231534.32278-5-me@tobin.cc> From: Randy Dunlap Message-ID: <7ce4d6ec-ef1b-1372-56bf-30ac1feabc9f@infradead.org> Date: Fri, 22 Jun 2018 09:21:32 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180621231534.32278-5-me@tobin.cc> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/21/2018 04:15 PM, Tobin C. Harding wrote: > Currently printing [hashed] pointers requires enough entropy to be > available. Early in the boot sequence this may not be the case > resulting in a dummy string '(____ptrval____)' being printed. This > makes debugging the early boot sequence difficult. We can relax the > requirement to use cryptographically secure hashing during debugging. > This enables debugging while keeping development/production kernel > behaviour the same. > > If new command line option debug_boot_weak_hash is enabled use > cryptographically insecure hashing and hash pointer value immediately. > > Reviewed-by: Steven Rostedt (VMware) > Signed-off-by: Tobin C. Harding Acked-by: Randy Dunlap Thanks. > --- > Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ > lib/vsprintf.c | 17 +++++++++++++++++ > 2 files changed, 25 insertions(+) -- ~Randy