From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x236.google.com (mail-wm0-x236.google.com [IPv6:2a00:1450:400c:c09::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yWRhv6b3tzDrKp for ; Tue, 7 Nov 2017 22:17:03 +1100 (AEDT) Received: by mail-wm0-x236.google.com with SMTP id y80so2921735wmd.0 for ; Tue, 07 Nov 2017 03:17:03 -0800 (PST) Date: Tue, 7 Nov 2017 14:16:58 +0300 From: "Kirill A. Shutemov" To: Florian Weimer Cc: Nicholas Piggin , "Aneesh Kumar K.V" , "Kirill A. Shutemov" , linuxppc-dev@lists.ozlabs.org, linux-mm , Andrew Morton , Andy Lutomirski , Dave Hansen , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-arch@vger.kernel.org, Ingo Molnar , Linux Kernel Mailing List Subject: Re: POWER: Unexpected fault when writing to brk-allocated memory Message-ID: <20171107111658.ifkbeg4dnlheabnr@node.shutemov.name> References: <20171105231850.5e313e46@roar.ozlabs.ibm.com> <871slcszfl.fsf@linux.vnet.ibm.com> <20171106174707.19f6c495@roar.ozlabs.ibm.com> <24b93038-76f7-33df-d02e-facb0ce61cd2@redhat.com> <20171106192524.12ea3187@roar.ozlabs.ibm.com> <546d4155-5b7c-6dba-b642-29c103e336bc@redhat.com> <20171107160705.059e0c2b@roar.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Nov 07, 2017 at 09:15:21AM +0100, Florian Weimer wrote: > MAP_FIXED is near-impossible to use correctly. I hope you don't expect > applications to do that. If you want address-based opt in, it should work > without MAP_FIXED. Sure, in obscure cases, applications might still see > out-of-range addresses, but I expected a full opt-out based on RLIMIT_AS > would be sufficient for them. Just use mmap(-1), without MAP_FIXED to get full address space. -- Kirill A. Shutemov