From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 6F0856B0038 for ; Mon, 25 Sep 2017 15:27:04 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id d6so10053979wrd.7 for ; Mon, 25 Sep 2017 12:27:04 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id w48sor2412577wrb.12.2017.09.25.12.27.02 for (Google Transport Security); Mon, 25 Sep 2017 12:27:03 -0700 (PDT) MIME-Version: 1.0 Reply-To: mtk.manpages@gmail.com In-Reply-To: <83b023da-e9f5-2957-981e-5b0e71e9bf1b@oracle.com> References: <20170919214224.19561-1-mike.kravetz@oracle.com> <6fafdae8-4fea-c967-f5cd-d22c205608fa@gmail.com> <83b023da-e9f5-2957-981e-5b0e71e9bf1b@oracle.com> From: "Michael Kerrisk (man-pages)" Date: Mon, 25 Sep 2017 21:26:42 +0200 Message-ID: Subject: Re: [patch v2] mremap.2: Add description of old_size == 0 functionality Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Mike Kravetz Cc: linux-man , "linux-mm@kvack.org" , lkml , Linux API , Jann Horn , Florian Weimer , Michal Hocko , Andrea Arcangeli , "Kirill A . Shutemov" , Vlastimil Babka , Anshuman Khandual Hi Mike, On 25 September 2017 at 18:33, Mike Kravetz wrote: > On 09/20/2017 12:25 AM, Michael Kerrisk (man-pages) wrote: [...] >> I've applied this, and added Reviewed-by tags for Florian and Jann. >> But, I think it's also worth noting the older, now disallowed, behavior, >> and why the behavior was changed. So I added a note in BUGS: >> >> 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 for the late reply Michael, I've been away for a few days. > > Yes, the above seems okay. Thanks for your help with this. You're welcome. Thanks for checking it over! Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- 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