Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765377AbXHQVTs (ORCPT ); Fri, 17 Aug 2007 17:19:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754651AbXHQVTf (ORCPT ); Fri, 17 Aug 2007 17:19:35 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:54668 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762570AbXHQVTd (ORCPT ); Fri, 17 Aug 2007 17:19:33 -0400 Date: Sat, 18 Aug 2007 03:02:14 +0530 (IST) From: Satyam Sharma X-X-Sender: satyam@enigma.security.iitk.ac.in To: Christoph Lameter cc: Andrew Morton , Arjan van de Ven , Tim Bird , linux kernel Subject: Re: kfree(0) - ok? In-Reply-To: Message-ID: References: <46C233CB.9000602@am.sony.com> <1187132149.2618.2.camel@laptopd505.fenrus.org> <20070817112253.e6a7cb33.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1207 Lines: 28 On Sat, 18 Aug 2007, Satyam Sharma wrote: > On Fri, 17 Aug 2007, Christoph Lameter wrote: > > > On Fri, 17 Aug 2007, Andrew Morton wrote: > > > > > are we seeing a pattern here? We could stick the unlikely inside > > > ZERO_OR_NULL_PTR() itself. That's a little bit sleazy though - there might > > > be future callsites at which it is likely, who knows? > > > > Thought about that myself but then there would be a weird side effect to > > ZERO_OR_NULL_PTR(). > > True, but I suspect such a side-effect to actually matter only for the > BUG_ON case, where introducing the unlikely() would mean the output from > the show_registers() dump during the BUG() would show a not-useful-at-all > %%eax == 0x0000001 value, but only if CONFIG_PROFILE_LIKELY=y, admittedly. Hang on, BUG_ON() already uses unlikely anyway. And I've just verified from a testcase that gcc doesn't get confused by unlikely(unlikely(...)) kind of code, so we're in the clear, I think. - 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/