Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935381AbdIYMlZ (ORCPT ); Mon, 25 Sep 2017 08:41:25 -0400 Received: from mail-wr0-f196.google.com ([209.85.128.196]:33344 "EHLO mail-wr0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933476AbdIYMlV (ORCPT ); Mon, 25 Sep 2017 08:41:21 -0400 X-Google-Smtp-Source: AOwi7QCGVf3hTQTvgXYRyIPlbUIoAqBzeoPh353JVnYUYUSEwkevlV8Rdna/++m08BV/YTna7VkJwHaqReXKf6S2dY8= MIME-Version: 1.0 Reply-To: mtk.manpages@gmail.com In-Reply-To: <20170925123621.35godwzhvw4wbisc@dhcp22.suse.cz> References: <20170919214224.19561-1-mike.kravetz@oracle.com> <6fafdae8-4fea-c967-f5cd-d22c205608fa@gmail.com> <20170925123621.35godwzhvw4wbisc@dhcp22.suse.cz> From: "Michael Kerrisk (man-pages)" Date: Mon, 25 Sep 2017 14:40:59 +0200 Message-ID: Subject: Re: [patch v2] mremap.2: Add description of old_size == 0 functionality To: Michal Hocko Cc: Mike Kravetz , linux-man , "linux-mm@kvack.org" , lkml , Linux API , Jann Horn , Florian Weimer , Andrea Arcangeli , "Kirill A . Shutemov" , Vlastimil Babka , Anshuman Khandual Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 958 Lines: 26 On 25 September 2017 at 14:36, Michal Hocko wrote: > On Wed 20-09-17 09:25:42, Michael Kerrisk wrote: > [...] >> BUGS >> Before Linux 4.14, if old_size was zero and the mapping referred >> to by old_address was a private mapping (mmap(2) MAP_PRIVATE), >> mremap() created a new private mapping unrelated to the original >> mapping. This behavior was unintended and probably unexpected in >> user-space applications (since the intention of mremap() is to >> create a new mapping based on the original mapping). Since Linux >> 4.14, mremap() fails with the error EINVAL in this scenario. >> >> Does that seem okay? > > sorry to be late but yes this wording makes perfect sense to me. Thanks, Michal. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/