From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261792AbVHDD5C (ORCPT ); Wed, 3 Aug 2005 23:57:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261793AbVHDD5C (ORCPT ); Wed, 3 Aug 2005 23:57:02 -0400 Received: from ms-smtp-02.nyroc.rr.com ([24.24.2.56]:40700 "EHLO ms-smtp-02.nyroc.rr.com") by vger.kernel.org with ESMTP id S261792AbVHDD5A (ORCPT ); Wed, 3 Aug 2005 23:57:00 -0400 Subject: Re: question on memory map of process on i386 From: Steven Rostedt To: Christopher Friesen Cc: Keith Owens , Linux Kernel Mailing List In-Reply-To: <42F15326.6000402@nortel.com> References: <42F15326.6000402@nortel.com> Content-Type: text/plain Organization: Kihon Technologies Date: Wed, 03 Aug 2005 23:56:07 -0400 Message-Id: <1123127767.1590.141.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2005-08-03 at 17:28 -0600, Christopher Friesen wrote: > On i386, /proc//maps shows the following entry: > > ffffe000-fffff000 ---p 00000000 00:00 0 > > This page of memory is way up above TASK_SIZE (which is 0xc0000000), so > how is it visible to userspace? > > Just to complicate things, I seem to find the vma for this page using > find_vma_prev(). > > Can anyone explain what's going on? > Looking at the code, it seems to be the "gate area". But what this is used for, I'm not really sure. I did a little searching but found no good explanations of it. So I added Keith to the CC since most of the updates to this was submitted by him :-) -- Steve