From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757994AbXI1Sxp (ORCPT ); Fri, 28 Sep 2007 14:53:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753274AbXI1Sxh (ORCPT ); Fri, 28 Sep 2007 14:53:37 -0400 Received: from ftp.linux-mips.org ([194.74.144.162]:48267 "EHLO ftp.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752425AbXI1Sxh (ORCPT ); Fri, 28 Sep 2007 14:53:37 -0400 Date: Fri, 28 Sep 2007 19:53:35 +0100 From: Ralf Baechle To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mips@linux-mips.org Subject: Re: [PATCH] hugetlb: Fix clear_user_highpage arguments Message-ID: <20070928185335.GA10976@linux-mips.org> References: <20070928163545.GA5933@linux-mips.org> <20070928114526.3398c462.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070928114526.3398c462.akpm@linux-foundation.org> User-Agent: Mutt/1.5.14 (2007-02-12) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 28, 2007 at 11:45:26AM -0700, Andrew Morton wrote: > > > The virtual address space argument of clear_user_highpage is supposed to > > be the virtual address where the page being cleared will eventually be > > mapped. This allows architectures with virtually indexed caches a few > > clever tricks. That sort of trick falls over in painful ways if the > > virtual address argument is wrong. > > yeah, but only if you're using a weird CPU architecture ;) I guess once I convinced your employer that weird CPU architectures deliver more punch for the watt they stop being so weird ;-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index 84c795e..eab8c42 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -42,7 +42,7 @@ static void clear_huge_page(struct page *page, unsigned long addr) > > might_sleep(); > > for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { > > cond_resched(); > > - clear_user_highpage(page + i, addr); > > + clear_user_highpage(page + i, addr + i * PAGE_SIZE); > > } > > } > > > > I'll add this to the 2.6.23 queue. Is it needed in 2.6.22.x? It's totally theoretical atm, MIPS doesn't support hugetlb and I'm not even working on it. I just happened to spot the issue. Ralf