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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F87BC433EF for ; Mon, 25 Jul 2022 08:37:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232095AbiGYIhR (ORCPT ); Mon, 25 Jul 2022 04:37:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229632AbiGYIhQ (ORCPT ); Mon, 25 Jul 2022 04:37:16 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 661DF13F89; Mon, 25 Jul 2022 01:37:15 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 135DDB80DDC; Mon, 25 Jul 2022 08:37:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 227FDC341C6; Mon, 25 Jul 2022 08:37:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1658738232; bh=+KW+70dQ2sLM3hx9zErNZIYUe9CxAaQYy2AEgGMfL94=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=vChsJmDaTSw9+lR6RVvvv11sDaBwCReHrjR18LsSLhq+QccNOGqfVj4LmDme6v3XF s9EOs0tlm8AyGwkZOcdwuYttxNkYi4+vS4prDnDDUIVtgJ9GiC+rAWRHM8Tt5vDzr0 AYRW1C1A76OALa02oVu/aG9S0k4OLsjcRf2esA8w= Date: Mon, 25 Jul 2022 10:37:07 +0200 From: Greg Kroah-Hartman To: Jiri Slaby Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Thadeu Lima de Souza Cascardo , Josh Poimboeuf , Peter Zijlstra , Borislav Petkov Subject: Re: [PATCH 5.18 13/70] objtool: skip non-text sections when adding return-thunk sites Message-ID: References: <20220722090650.665513668@linuxfoundation.org> <20220722090651.464856922@linuxfoundation.org> <8a4f10b1-70b3-25fe-9ffc-4f24a1531139@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8a4f10b1-70b3-25fe-9ffc-4f24a1531139@kernel.org> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jul 25, 2022 at 07:44:08AM +0200, Jiri Slaby wrote: > Hi, > > I wonder, why this is needed in stable and not mainline? > > Isn't this a different (non-upstream) dup of > 951ddecf4356 objtool: Treat .text.__x86.* as noinstr > ? (That is included in this release too.) > > On 22. 07. 22, 11:07, Greg Kroah-Hartman wrote: > > From: Thadeu Lima de Souza Cascardo > > > > The .discard.text section is added in order to reserve BRK, with a > > temporary function just so it can give it a size. This adds a relocation to > > the return thunk, which objtool will add to the .return_sites section. > > Linking will then fail as there are references to the .discard.text > > section. > > > > Do not add instructions from non-text sections to the list of return thunk > > calls, avoiding the reference to .discard.text. > > > > Signed-off-by: Thadeu Lima de Souza Cascardo > > Acked-by: Josh Poimboeuf > > Signed-off-by: Greg Kroah-Hartman > > --- > > tools/objtool/check.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > --- a/tools/objtool/check.c > > +++ b/tools/objtool/check.c > > @@ -1308,7 +1308,9 @@ static void add_return_call(struct objto > > insn->type = INSN_RETURN; > > insn->retpoline_safe = true; > > - list_add_tail(&insn->call_node, &file->return_thunk_list); > > + /* Skip the non-text sections, specially .discard ones */ > > + if (insn->sec->text) > > + list_add_tail(&insn->call_node, &file->return_thunk_list); > > } > > static bool same_function(struct instruction *insn1, struct instruction *insn2) > > > > I'll let Thadeu reply here, as he did this backport series. thanks, greg k-h