From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759091Ab3BMKM5 (ORCPT ); Wed, 13 Feb 2013 05:12:57 -0500 Received: from mail-wi0-f182.google.com ([209.85.212.182]:57462 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758375Ab3BMKMz (ORCPT ); Wed, 13 Feb 2013 05:12:55 -0500 Message-ID: <1360750028.24917.28.camel@mfleming-mobl1.ger.corp.intel.com> Subject: Re: [PATCH V3] ia64/mm: fix a bad_page bug when crash kernel booting From: Matt Fleming To: Xishi Qiu Cc: "Luck, Tony" , fenghua.yu@intel.com, Liujiang , Andrew Morton , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org, linux-mm@kvack.org, Hanjun Guo , WuJianguo Date: Wed, 13 Feb 2013 10:07:08 +0000 In-Reply-To: <5113450C.1080109@huawei.com> References: <51074786.5030007@huawei.com> <1359995565.7515.178.camel@mfleming-mobl1.ger.corp.intel.com> <51131248.3080203@huawei.com> <5113450C.1080109@huawei.com> Organization: Intel Corporation (UK) Ltd. - Registered No. 1134945 - Pipers Way, Swindon SN3 1RJ Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4 (3.4.4-2.fc17) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-02-07 at 14:09 +0800, Xishi Qiu wrote: > > Sorry, this bug will be happen when use Sparse-Memory(section is valid, but last > > > several pages are invalid). If use Flat-Memory, crash kernel will boot successfully. > > I think the following patch would be better. > > > > Hi Andrew, will you just ignore the earlier patch and consider the following one? :> > > > > Signed-off-by: Xishi Qiu > > --- > > arch/ia64/mm/init.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c > > index 082e383..23f2ee3 100644 > > --- a/arch/ia64/mm/init.c > > +++ b/arch/ia64/mm/init.c > > @@ -213,6 +213,8 @@ free_initrd_mem (unsigned long start, unsigned long end) > > for (; start < end; start += PAGE_SIZE) { > > if (!virt_addr_valid(start)) > > continue; > > + if ((start >> PAGE_SHIFT) >= max_low_pfn) > > I confused the vaddr and paddr, really sorry for it. > > In efi_init() memory aligns in IA64_GRANULE_SIZE(16M). If set "crashkernel=1024M-:600M" > and use sparse memory model, when crash kernel booting it changes [128M-728M] to [128M-720M]. > But initrd memory is in [709M-727M], and virt_addr_valid() *can not* check the invalid pages > when freeing initrd memory. There are some pages missed at the end of the seciton. > > ChangeLog V3: > fixed vaddr mistake > ChangeLog V2: > add invalid pages check when freeing initrd memory > > Signed-off-by: Xishi Qiu > --- > arch/ia64/mm/init.c | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c > index 082e383..8a269f8 100644 > --- a/arch/ia64/mm/init.c > +++ b/arch/ia64/mm/init.c > @@ -173,6 +173,7 @@ void __init > free_initrd_mem (unsigned long start, unsigned long end) > { > struct page *page; > + unsigned long pfn; > /* > * EFI uses 4KB pages while the kernel can use 4KB or bigger. > * Thus EFI and the kernel may have different page sizes. It is > @@ -213,6 +214,9 @@ free_initrd_mem (unsigned long start, unsigned long end) > for (; start < end; start += PAGE_SIZE) { > if (!virt_addr_valid(start)) > continue; > + pfn = __pa(start) >> PAGE_SHIFT; > + if (pfn >= max_low_pfn) > + continue; > page = virt_to_page(start); > ClearPageReserved(page); > init_page_count(page); I would have presumed that fixing this bug would involve modifying the ia64-specific kexec code? Tony, Fenghua? Any thoughts?