From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f200.google.com (mail-yw0-f200.google.com [209.85.161.200]) by kanga.kvack.org (Postfix) with ESMTP id AA7396B0005 for ; Fri, 8 Jul 2016 04:46:44 -0400 (EDT) Received: by mail-yw0-f200.google.com with SMTP id l125so75095301ywb.2 for ; Fri, 08 Jul 2016 01:46:44 -0700 (PDT) Received: from mail-qt0-x241.google.com (mail-qt0-x241.google.com. [2607:f8b0:400d:c0d::241]) by mx.google.com with ESMTPS id g67si1397985qkh.329.2016.07.08.01.46.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Jul 2016 01:46:43 -0700 (PDT) Received: by mail-qt0-x241.google.com with SMTP id h56so2442081qte.2 for ; Fri, 08 Jul 2016 01:46:43 -0700 (PDT) Date: Fri, 8 Jul 2016 10:46:39 +0200 From: Ingo Molnar Subject: Re: [PATCH 0/9] mm: Hardened usercopy Message-ID: <20160708084639.GA4562@gmail.com> References: <1467843928-29351-1-git-send-email-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1467843928-29351-1-git-send-email-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-ID: To: Kees Cook Cc: linux-kernel@vger.kernel.org, Rik van Riel , Casey Schaufler , PaX Team , Brad Spengler , Russell King , Catalin Marinas , Will Deacon , Ard Biesheuvel , Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , Fenghua Yu , "David S. Miller" , x86@kernel.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Andy Lutomirski , Borislav Petkov , Mathias Krause , Jan Kara , Vitaly Wool , Andrea Arcangeli , Dmitry Vyukov , Laura Abbott , linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Linus Torvalds , Thomas Gleixner , "H. Peter Anvin" , Peter Zijlstra * Kees Cook wrote: > - I couldn't detect a measurable performance change with these features > enabled. Kernel build times were unchanged, hackbench was unchanged, > etc. I think we could flip this to "on by default" at some point. Could you please try to find some syscall workload that does many small user copies and thus excercises this code path aggressively? If that measurement works out fine then I'd prefer to enable these security checks by default. Thaks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org