From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964883AbWFSUMh (ORCPT ); Mon, 19 Jun 2006 16:12:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964884AbWFSUMg (ORCPT ); Mon, 19 Jun 2006 16:12:36 -0400 Received: from ik55118.ikexpress.com ([213.246.55.118]:22166 "EHLO ik55118.ikexpress.com") by vger.kernel.org with ESMTP id S964883AbWFSUMf (ORCPT ); Mon, 19 Jun 2006 16:12:35 -0400 Message-ID: <44970522.9030404@free-electrons.com> Date: Mon, 19 Jun 2006 22:12:18 +0200 From: Michael Opdenacker User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: "linux-os (Dick Johnson)" , chase.venters@clientec.com Cc: Linux Kernel Mailing List Subject: Re: Option to clear allocated kernel memory before freeing it? References: <4496B92A.3010907@free-electrons.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Chase, Dick, > No. Memory is cleared before being mapped to user-space. Memory > that is allocated for use by the kernel is never cleared by default. > To do so would waste valuable time for nothing gained. > > >> Unless I'm missing something, uncleared memory previously used for >> kernel allocations could later be recycled for user allocations, making >> it possible for a user program to access sensitive driver data if it's >> lucky. >> > > Wrong. You are missing a lot. > Oops, I realize I was really missing a lot! Thank you very much for leading me to the right path! Cheers, Michael. -- Michael Opdenacker, Free Electrons Free Embedded Linux Training Materials on http://free-electrons.com/training (More than 1000 pages!)..