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 9A32AC77B7E for ; Thu, 25 May 2023 19:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233627AbjEYTjd (ORCPT ); Thu, 25 May 2023 15:39:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232203AbjEYTjd (ORCPT ); Thu, 25 May 2023 15:39:33 -0400 X-Greylist: delayed 1188 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Thu, 25 May 2023 12:39:03 PDT Received: from smtp.outflux.net (mta.outflux.net [IPv6:2001:19d0:2:6:c0de:0:736d:7471]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9175101 for ; Thu, 25 May 2023 12:39:03 -0700 (PDT) Received: from serenity.outflux.net (serenity.outflux.net [10.2.0.2]) by vinyl.outflux.net (8.15.2/8.15.2/Debian-10) with ESMTP id 34PIeYCD025811; Thu, 25 May 2023 11:40:34 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=outflux.net; s=2016010; t=1685040034; bh=9zwtAfyKF73stEa8mnj95uzHY/DupItIN7pSr8gdlHY=; h=Date:From:To:Cc:Subject:From; b=suyALfLFerSxQu4aHfUApIxWgxMlsLWM5WmEIEkT0K8HhWTgRglPKBLTfliOPAPrN fc5hQTEFRcL2pdtd0WMLEXv7KzrWwsDFM+Atw6y8DZwQQHKSCJHJZyzmJyI/1L426A GhG6BdUkNUAZ2UFL3AyaJPNo4uDErH9AcQWDFFmE= Date: Thu, 25 May 2023 11:40:34 -0700 From: Kees Cook To: Heiko Carstens , Alexander Gordeev Cc: linux-hardening@vger.kernel.org Subject: Re: s390/defconfigs: set CONFIG_INIT_STACK_NONE=y Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Organization: Outflux X-MIMEDefang-Filter: outflux$Revision: 1.316 $ X-HELO: serenity.outflux.net Envelope-To: linux-hardening@vger.kernel.org Envelope-To: hca@linux.ibm.com Envelope-To: agordeev@linux.ibm.com X-Scanned-By: MIMEDefang 2.83 Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Hi Heiko, I had this[1] patch pointed out to me, but I couldn't find any discussion about it on public lists. Can you give me some background on this? There haven't been any general workloads identified where this has been a problem, so I'm curious why this was seen as globally an issue on s390. The expectation was to use __uninitialized on any variables where this was noticed as a performance issue, and where the memory safety of the variable could be proven. Turning it off by default seems like rather too much, but perhaps there is something unique to s390 I don't know about. :) Thanks, -Kees [1] https://git.kernel.org/linus/124acbe275040809abfa5fbe6e25790a53d5a161 -- Kees Cook @outflux.net