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=-3.8 required=3.0 tests=BAYES_00,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 EA784C388F7 for ; Thu, 22 Oct 2020 07:26:28 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 94E05222E9 for ; Thu, 22 Oct 2020 07:26:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="aUN68Sfz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94E05222E9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20248-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 13402 invoked by uid 550); 22 Oct 2020 07:26:18 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 13379 invoked from network); 22 Oct 2020 07:26:18 -0000 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; bh=h+rKHFkcR5k6QSt8CeK8lSdFFr+MaETwBr6Mxg4PDmU=; b=aUN68SfzWTPeVbTNit8fy/ZXb0 rRAYaTV5InvSpscM+g5V5UNuxxMIOSNNjdTrr9zBJwTDnIr7HB4kAtF5eelSvpZSzfzi0XB65k49y fMhVyhLkrBDvMABUemD6zpOEa+Q8IzTJx4IZksVwvVIaYHLDJx476sb1mRX2HLMmaKAybchSbXO5G h2Y+yNlzpY2780AC98N7ePm2EJ79MCEo33CoAfryNdBPReXIr4iTyNLwA3Ag8rPF1QkdzEXKCnmAv 01B8rB6S0TBGhXUXekjoFY4MHksCyJY7O4ahmGFdB9hvjhmJ+hNdIUNrUYqknMjnfiTaSOjgjEbDG qxHU9c4w==; Date: Thu, 22 Oct 2020 09:25:53 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: Sami Tolvanen , Jann Horn , the arch/x86 maintainers , Masahiro Yamada , Steven Rostedt , Will Deacon , Greg Kroah-Hartman , "Paul E. McKenney" , Kees Cook , Nick Desaulniers , clang-built-linux , Kernel Hardening , linux-arch , Linux ARM , linux-kbuild , kernel list , linux-pci@vger.kernel.org Subject: Re: [PATCH v6 22/25] x86/asm: annotate indirect jumps Message-ID: <20201022072553.GN2628@hirez.programming.kicks-ass.net> References: <20201013003203.4168817-23-samitolvanen@google.com> <20201015102216.GB2611@hirez.programming.kicks-ass.net> <20201015203942.f3kwcohcwwa6lagd@treble> <20201020185217.ilg6w5l7ujau2246@treble> <20201021085606.GZ2628@hirez.programming.kicks-ass.net> <20201021093213.GV2651@hirez.programming.kicks-ass.net> <20201021212747.ofk74lugt4hhjdzg@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201021212747.ofk74lugt4hhjdzg@treble> On Wed, Oct 21, 2020 at 04:27:47PM -0500, Josh Poimboeuf wrote: > On Wed, Oct 21, 2020 at 11:32:13AM +0200, Peter Zijlstra wrote: > > On Wed, Oct 21, 2020 at 10:56:06AM +0200, Peter Zijlstra wrote: > > > > > I do not see these in particular, although I do see a lot of: > > > > > > "sibling call from callable instruction with modified stack frame" > > > > defconfig-build/vmlinux.o: warning: objtool: msr_write()+0x10a: sibling call from callable instruction with modified stack frame > > defconfig-build/vmlinux.o: warning: objtool: msr_write()+0x99: (branch) > > defconfig-build/vmlinux.o: warning: objtool: msr_write()+0x3e: (branch) > > defconfig-build/vmlinux.o: warning: objtool: msr_write()+0x0: <=== (sym) > > > > $ nm defconfig-build/vmlinux.o | grep msr_write > > 0000000000043250 t msr_write > > 00000000004289c0 T msr_write > > 0000000000003056 t msr_write.cold > > > > Below 'fixes' it. So this is also caused by duplicate symbols. > > There's a new linker flag for renaming duplicates: > > https://sourceware.org/bugzilla/show_bug.cgi?id=26391 > > But I guess that doesn't help us now. Well, depends a bit if clang can do it; we only need this for LTO builds for now. > I don't have access to GCC 10 at the moment so I can't recreate it. > Does this fix it? Doesn't seem to do the trick :/ I'll try and have a poke later.