Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758327AbYFQVZQ (ORCPT ); Tue, 17 Jun 2008 17:25:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752803AbYFQVZF (ORCPT ); Tue, 17 Jun 2008 17:25:05 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:34907 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751605AbYFQVZD (ORCPT ); Tue, 17 Jun 2008 17:25:03 -0400 Date: Tue, 17 Jun 2008 14:24:39 -0700 (PDT) From: Linus Torvalds To: Andi Kleen cc: Bron Gondwana , Linux Kernel Mailing List , Nick Piggin , Andrew Morton , Rob Mueller , Ingo Molnar Subject: Re: BUG: mmapfile/writev spurious zero bytes (x86_64/not i386, bisected, reproducable) In-Reply-To: <485829A1.4020705@firstfloor.org> Message-ID: References: <1213682410.13174.1258837181@webmail.messagingengine.com> <1213682570.13708.1258839317@webmail.messagingengine.com> <485829A1.4020705@firstfloor.org> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) 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 Content-Length: 1133 Lines: 28 On Tue, 17 Jun 2008, Andi Kleen wrote: > > If that fixes anything: > - The caller is broken because it shouldn't pass a faulting source to copy_to_user() > - And you broken copy_from_user error reporting which shares the same code Andi, I'm sorry I cc'd you. You are the author of that crap, but the bug seems to be that you never even understood what copy_from_user() is supposed to do. The whole *and*only* reason for copy_to/from_user() existing AT ALL is exactly the fact that the source or destination access can fault. I don't really see why you continually start arguing about things that are OBVIOUSLY BUGGY, as if they weren't buggy. Once somebody has debugged a buggy routine, you shouldn't argue against it. So here's a hint: next time I claim some code of yours is buggy, either just acknowledge the bug, or stay silent. You'll look smarter that way. Linus -- 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/