From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762995AbYB0IC4 (ORCPT ); Wed, 27 Feb 2008 03:02:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753435AbYB0ICs (ORCPT ); Wed, 27 Feb 2008 03:02:48 -0500 Received: from www.tglx.de ([62.245.132.106]:56591 "EHLO www.tglx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753116AbYB0ICr (ORCPT ); Wed, 27 Feb 2008 03:02:47 -0500 Date: Wed, 27 Feb 2008 09:02:22 +0100 (CET) From: Thomas Gleixner To: David Miller cc: mikpe@it.uu.se, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] 2.6.25-rc3 hangs in early boot on Sun Ultra5 In-Reply-To: <20080226.170613.107688605.davem@davemloft.net> Message-ID: References: <18371.10207.58819.188510@alkaid.it.uu.se> <18371.54294.748777.976300@harpo.it.uu.se> <20080226.164900.193701385.davem@davemloft.net> <20080226.170613.107688605.davem@davemloft.net> User-Agent: Alpine 1.00 (LFD 882 2007-12-20) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Feb 2008, David Miller wrote: > What the FUTEX checking code is doing now is doing a "user" access > with set_fs(KERNEL_DS) since it runs from the kernel bootup early init > sequence. And this is illegal according to the existing checks. > > When we do set_fs(KERNEL_DS) then pass a "user" pointer down > into a system call or something like that, we give it a pointer > that "cannot fault". So if we get into the fault handling > path here for a case like that we really do want to scream and > print out an OOPS message in my opinion. So it would be correct to set_fs(USER_DS) then do the check and switch back to KERNEL_DS ? > I realize that not many platforms other than sparc64 can check > for things this precisely, but it's something to consider. Hmm, I missed that. > Did this FUTEX change go into -stable too? It's queued, AFAIK Thanks, tglx