Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752135AbbKKBWc (ORCPT ); Tue, 10 Nov 2015 20:22:32 -0500 Received: from mail-yk0-f177.google.com ([209.85.160.177]:34678 "EHLO mail-yk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751760AbbKKBWb (ORCPT ); Tue, 10 Nov 2015 20:22:31 -0500 MIME-Version: 1.0 In-Reply-To: References: Date: Tue, 10 Nov 2015 17:22:30 -0800 Message-ID: Subject: Re: init: How did init/do_mounts_rd.c overcome memory protection ? From: Badhri Jagan Sridharan To: Richard Weinberger Cc: LKML , David Howells , Andrew Morton 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: 1193 Lines: 31 Thanks Richard !! That's the one that I was looking for. On Tue, Nov 10, 2015 at 1:37 PM, Richard Weinberger wrote: > On Tue, Nov 10, 2015 at 7:38 PM, Badhri Jagan Sridharan > wrote: >> Mighty upstream, >> >> I see that do_mounts_rd.c seems to make calls to sys_read and >> sys_lseek functions. As these are syscall functions, they expects >> some of the arguments to be from userspace. >> >> I was going through the article that Greg KH wrote a while back: >> http://www.linuxjournal.com/article/8110?page=0,1 . I don't see any >> references to set_fs/get_fs under init/*. Does the memory protection >> get enabled only in the later stage ? Or does do_mounts_rd.c accomplish >> this in some other way ? > > The stuff in init/ is PID 1 and it inherits addr_limit from the > initial thread (PID 0 or swapper called). > INIT_THREAD_INFO() sets addr_limit to KERNEL_DS. > > -- > Thanks, > //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/