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 6566AC4332F for ; Fri, 10 Nov 2023 21:33:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229471AbjKJVdx convert rfc822-to-8bit (ORCPT ); Fri, 10 Nov 2023 16:33:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229537AbjKJVdx (ORCPT ); Fri, 10 Nov 2023 16:33:53 -0500 Received: from smtp.gentoo.org (mail.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C793A9 for ; Fri, 10 Nov 2023 13:33:50 -0800 (PST) References: <87lebjz9z6.fsf@gentoo.org> <875y2jro9a.fsf@gentoo.org> <0fec2446-a523-486f-9df7-4c6af9e2e0e3@gmx.de> <7409ec05-7a28-45fe-9604-519de5ae934e@bell.net> User-agent: mu4e 1.10.8; emacs 30.0.50 From: Sam James To: John David Anglin Cc: Helge Deller , Sam James , "linux-parisc@vger.kernel.org" Subject: Re: prctl call wrongly succeeds on HPPA? Date: Fri, 10 Nov 2023 21:32:50 +0000 Organization: Gentoo In-reply-to: Message-ID: <87sf5d8f9h.fsf@gentoo.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org John David Anglin writes: > On 2023-11-10 3:38 p.m., Helge Deller wrote: >> On 11/10/23 21:12, John David Anglin wrote: >>> On 2023-11-10 3:01 p.m., Helge Deller wrote: >>>>>> On HPPA, we still need executable stacks, so this option doesn't work >>>>>> and leads to a segfault on boot. >>>> >>>> For kernel we don't need it any longer. >>>> But there might be dependencies on glibc version and/or combination. >>>> So, I've currently lost overview if we still need executable stacks... >>> FWIW, I recently changed gcc-14 to enable GNU stack notes and fixed a bug in the >>> 32-bit PA 2.0 trampoline template.  All execute stack tests in glibc now pass with gcc-14. >> >> Yes, I saw your commits. >> So, any code compiled with >= gcc-14 should be fine with non-writeable stacks? > Not exactly.  An executable stack is still needed for nested functions.  They are still called > via a stack trampoline.  The GNU stack note indicates whether an object needs an executable > stack or not.  These notes are collected by linker.  The glibc loader determines whether to setup > an executable stack or not. >> It would be easier if it would be a glibc dependency (for distribution maintainers)... > I'm not aware of any glibc dependency... > > I think once gcc-14 becomes the default compiler, we will have to enable GNU stack notes in > previous gcc versions.  We will still have executable stacks until everything is rebuilt. We will need to update that default in Binutils too, I think. That configure arg is working OK for me, but I did not try systemd yet. > > Dave