From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756554AbYDJMJR (ORCPT ); Thu, 10 Apr 2008 08:09:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755198AbYDJMJD (ORCPT ); Thu, 10 Apr 2008 08:09:03 -0400 Received: from ns.suse.de ([195.135.220.2]:59996 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752333AbYDJMJC (ORCPT ); Thu, 10 Apr 2008 08:09:02 -0400 From: Andreas Schwab To: Johannes Weiner Cc: Roel Kluin <12o3l@tiscali.nl>, linux-mm@kvack.org, lkml Subject: Re: [PATCH] pagewalk: don't pte_unmap(NULL) in walk_pte_range() References: <47FC95AD.1070907@tiscali.nl> <87zls3qhop.fsf@saeurebad.de> X-Yow: I'm sitting on my SPEED QUEEN.. To me, it's ENJOYABLE.. I'm WARM.. I'm VIBRATORY.. Date: Thu, 10 Apr 2008 14:09:00 +0200 In-Reply-To: <87zls3qhop.fsf@saeurebad.de> (Johannes Weiner's message of "Wed\, 09 Apr 2008 15\:30\:30 +0200") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/22.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Johannes Weiner writes: >> Signed-off-by: Roel Kluin <12o3l@tiscali.nl> >> --- >> diff --git a/mm/pagewalk.c b/mm/pagewalk.c >> index 1cf1417..6615f0b 100644 >> --- a/mm/pagewalk.c >> +++ b/mm/pagewalk.c >> @@ -15,7 +15,7 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, >> break; >> } while (pte++, addr += PAGE_SIZE, addr != end); >> >> - pte_unmap(pte); >> + pte_unmap(pte - 1); >> return err; >> } > > This does not make any sense to me. There is something fishy here. If the loop ends because addr == end then pte has been incremented past the pmd page for addr, no? Andreas. -- Andreas Schwab, SuSE Labs, schwab@suse.de SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."