From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 6CD24B6F14 for ; Wed, 9 Dec 2009 18:08:52 +1100 (EST) Subject: Re: Badness at arch/powerpc/mm/pgtable.c:286 From: Benjamin Herrenschmidt To: kordex - In-Reply-To: <8b8dd87a0912080914h3d71ea6x3052582b662d5f73@mail.gmail.com> References: <8b8dd87a0912080914h3d71ea6x3052582b662d5f73@mail.gmail.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 09 Dec 2009 18:08:44 +1100 Message-ID: <1260342524.16132.28.camel@pasglop> Mime-Version: 1.0 Cc: linuxppc-dev , linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2009-12-08 at 19:14 +0200, kordex - wrote: > Hello, > > I turned some debuging options in order to trace rcutree problems but > after turning debugging on it began just to loop on this: > > http://xnet.fi/opt/pics/pgtable_badness.jpg > 1.5M pgtable_badness.jpg > > I am sorry that I could not produce full dmesg. > > Kernel config: http://xnet.fi/opt/apps/lkml-2.6.32-vanilla.debug.config.txt Thanks for your report. Does that patch fixes it ? powerpc/mm: Fix a WARN_ON() with CONFIG_DEBUG_PAGEALLOC and CONFIG_DEBUG_VM Set need to call __set_pte_at() and not set_pte_at() from __change_page_attr() since the later will perform checks with CONFIG_DEBUG_VM that aren't suitable to the way we override an existing PTE. (More specifically, it doesn't let you write over a present PTE). Signed-off-by: Benjamin Herrenschmidt --- Index: linux-work/arch/powerpc/mm/pgtable_32.c =================================================================== --- linux-work.orig/arch/powerpc/mm/pgtable_32.c 2009-12-09 18:06:14.000000000 +1100 +++ linux-work/arch/powerpc/mm/pgtable_32.c 2009-12-09 18:06:16.000000000 +1100 @@ -356,7 +356,7 @@ static int __change_page_attr(struct pag return 0; if (!get_pteptr(&init_mm, address, &kpte, &kpmd)) return -EINVAL; - set_pte_at(&init_mm, address, kpte, mk_pte(page, prot)); + __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot)); wmb(); #ifdef CONFIG_PPC_STD_MMU flush_hash_pages(0, address, pmd_val(*kpmd), 1);