From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 01F516B0069 for ; Tue, 3 Jan 2017 17:07:32 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id iq1so51817592wjb.1 for ; Tue, 03 Jan 2017 14:07:31 -0800 (PST) Received: from mout.kundenserver.de (mout.kundenserver.de. [212.227.126.130]) by mx.google.com with ESMTPS id e70si75078584wmc.129.2017.01.03.14.07.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Jan 2017 14:07:30 -0800 (PST) From: Arnd Bergmann Subject: Re: [RFC, PATCHv2 29/29] mm, x86: introduce RLIMIT_VADDR Date: Tue, 03 Jan 2017 23:07:20 +0100 Message-ID: <21511994.eBlbEPoKOz@wuerfel> In-Reply-To: References: <20161227015413.187403-1-kirill.shutemov@linux.intel.com> <3492795.xaneWtGxgW@wuerfel> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: "Kirill A. Shutemov" , Linus Torvalds , Andrew Morton , X86 ML , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andi Kleen , Dave Hansen , linux-arch , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Linux API , "linux-arm-kernel@lists.infradead.org" , Catalin Marinas , Will Deacon On Tuesday, January 3, 2017 10:29:33 AM CET Andy Lutomirski wrote: > > Hmm. What if we approached this a bit differently? We could add a > single new personality bit ADDR_LIMIT_EXPLICIT. Setting this bit > cause PER_LINUX32_3GB etc to be automatically cleared. Both the ADDR_LIMIT_32BIT and ADDR_LIMIT_3GB flags I guess? > When > ADDR_LIMIT_EXPLICIT is in effect, prctl can set a 64-bit numeric > limit. If ADDR_LIMIT_EXPLICIT is cleared, the prctl value stops being > settable and reading it via prctl returns whatever is implied by the > other personality bits. I don't see anything wrong with it, but I'm a bit confused now what this would be good for, compared to using just prctl. Is this about setuid clearing the personality but not the prctl, or something else? Arnd -- 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