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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT 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 7CAE0C43142 for ; Mon, 25 Jun 2018 09:22:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 344E1256A1 for ; Mon, 25 Jun 2018 09:22:58 +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="QS9kGyD7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 344E1256A1 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 S1755022AbeFYJW4 (ORCPT ); Mon, 25 Jun 2018 05:22:56 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46700 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754753AbeFYJWy (ORCPT ); Mon, 25 Jun 2018 05:22:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding: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=pZpuGCAqa9fPwHqUmnsy91+PnI9rtLAf81BB5Twlms0=; b=QS9kGyD7C3FA+6h7n2DYYSAfp IERye8td9xD2YXbjb/+eofMOsogh7cvPJTwseogpjUmVBktXdWo0LD4XiqAjimIGanDVP3nkI+orZ WwJ7tsEGd61JLlookWKChKdXJkYD1RIrg6wdumunqwfBn4fZj5KBddIhS6S55pVWajFXaxTBPZl00 g5cY68CDF36AqdMyx/GyfDfXUrU0TS4PYcfhYctSUHcaFZgGfbJibh9RijaFvxRUbTKwPSw/3Z9Jg /ErZzfV6wZe3hp0NJF++dg5rKAR2wRPKOcY/e/1Er4n+cpSp6QfDGLj6iJRWk4pU3EWGs4kSYPJcI r2FOo+r0A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fXNhe-0006hw-CK; Mon, 25 Jun 2018 09:22:30 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2A7872029F1D7; Mon, 25 Jun 2018 11:22:29 +0200 (CEST) Date: Mon, 25 Jun 2018 11:22:29 +0200 From: Peter Zijlstra To: Thomas Gleixner Cc: Pavel Tatashin , steven.sistare@oracle.com, daniel.m.jordan@oracle.com, linux@armlinux.org.uk, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, john.stultz@linaro.org, sboyd@codeaurora.org, x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, douly.fnst@cn.fujitsu.com, prarit@redhat.com, feng.tang@intel.com, pmladek@suse.com, gnomes@lxorguk.ukuu.org.uk, linux-s390@vger.kernel.org, Steven Rostedt Subject: Re: [PATCH v12 01/11] x86: text_poke() may access uninitialized struct pages Message-ID: <20180625092229.GW2494@hirez.programming.kicks-ass.net> References: <20180621212518.19914-1-pasha.tatashin@oracle.com> <20180621212518.19914-2-pasha.tatashin@oracle.com> <20180625081429.GS2494@hirez.programming.kicks-ass.net> <20180625090915.GV2494@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 25, 2018 at 11:18:02AM +0200, Thomas Gleixner wrote: > On Mon, 25 Jun 2018, Peter Zijlstra wrote: > > On Mon, Jun 25, 2018 at 10:39:24AM +0200, Thomas Gleixner wrote: > > > On Mon, 25 Jun 2018, Peter Zijlstra wrote: > > > > I'm not entirely sure this is right.. Because not only do we need the > > > > whole fixmap stuff working, we also need #DB and the IPI handlers set-up > > > > and working. > > > > > > IPI? That's early UP boot why would you need an IPI? > > > > Because the way this is called is from __jump_label_transform() -> > > text_poke_bp() -> text_poke() -> text_poke_early(). > > > > And if you look at text_poke_bp(), you'll note it relies on #DB and > > on_each_cpu() IPIs. > > on_each_cpu() resolves to a direct call on the current CPU and as there is > no other CPU it does not matter. #DB might be a different story, haven't > looked yet. It _should_ all work.. but scary, who knows where this early stuff ends up being used.