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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 48D8EC433DB for ; Tue, 16 Feb 2021 15:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2547D64D9F for ; Tue, 16 Feb 2021 15:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbhBPPrO (ORCPT ); Tue, 16 Feb 2021 10:47:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:43491 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229708AbhBPPrM (ORCPT ); Tue, 16 Feb 2021 10:47:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613490345; 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=86vWmVPfoSGSBR3M7oLmyUrscE6/3lgafW3QD8JX7cw=; b=KdjZQQpCJsxcifaBVHa0oGHABOc3NspqHfD0YZsJCYdwat/38K6PV8VSALOSfVRg3Dwwox EwMglVCWSx3mszcCs7cStloh/B2qLhhUMLnQ58zk+oVcHVeBzu/KwhqcbtOanoHLHQHiPJ zbyD4nBYpm5ve35TsbETMv+UvzDMvIg= 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-76-lLdBOu2jPMaaW2HlVzcBcA-1; Tue, 16 Feb 2021 10:45:44 -0500 X-MC-Unique: lLdBOu2jPMaaW2HlVzcBcA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D8530100CCC0; Tue, 16 Feb 2021 15:45:42 +0000 (UTC) Received: from treble (ovpn-117-118.rdu2.redhat.com [10.10.117.118]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1AEED1975F; Tue, 16 Feb 2021 15:45:41 +0000 (UTC) Date: Tue, 16 Feb 2021 09:45:39 -0600 From: Josh Poimboeuf To: Steven Rostedt Cc: Greg Kroah-Hartman , LKML , Ingo Molnar , Andrew Morton Subject: Re: [PATCH] ftrace: Do not reference symbols in sections without size Message-ID: <20210216154539.qac763oef4czrtss@treble> References: <20210215164446.530f6311@gandalf.local.home> <20210216000504.axm3k4xho47c6drz@treble> <20210215200639.67141685@oasis.local.home> <20210215210057.4ceb6339@oasis.local.home> <20210216095121.4fe321dc@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210216095121.4fe321dc@gandalf.local.home> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 16, 2021 at 09:51:21AM -0500, Steven Rostedt wrote: > On Tue, 16 Feb 2021 12:04:06 +0100 > Greg Kroah-Hartman wrote: > > > Thanks for this. > > > > Should I also queue these up for 4.9 and 4.14 which do not have these > > commits in them either (but somehow do not show the problem, yet)? > > This bothers me. I want to know exactly why this is a problem. I actually see the same problem with 4.9 and 4.14, using the same config. It's very config-specific. Something has to convince the toolchain to not reference those two weak functions by section. > That said, it is fine to backport those patches, and I would include 4.9 > and 4.14, as I would think you have a similar requirement that we have in > the stable-rt trees. That is you shouldn't experience a regression going > from an older kernel to a newer one because the older one had a fix > backported to it that a newer one did not. Basically the same rationale that > all fixes go into Linus's tree before backporting. We do the same on the > stable-rt, where all fixes go in all maintained stable trees that are newer > than the one you are backporting to. > > Although, it does allow more to be traced than what recordmcount enables. > But hopefully it doesn't cause any issues. Maybe I should do some ftrace > testing before you go and release any of those stables with those patches. > > I'm looking to see if this new "feature" of binutils isn't causing trouble > elsewhere. I'm thinking that ftrace is just the canary here. It already caused quite a bit of trouble with objtool (as did a previous similar change by the Clang assembler). -- Josh