From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755410Ab0AMOAi (ORCPT ); Wed, 13 Jan 2010 09:00:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755385Ab0AMOAg (ORCPT ); Wed, 13 Jan 2010 09:00:36 -0500 Received: from mga11.intel.com ([192.55.52.93]:2955 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755013Ab0AMOAe (ORCPT ); Wed, 13 Jan 2010 09:00:34 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.49,268,1262592000"; d="scan'208";a="763861776" Message-Id: <20100113135958.291404947@intel.com> User-Agent: quilt/0.48-1 Date: Wed, 13 Jan 2010 21:53:13 +0800 From: Wu Fengguang To: Andrew Morton Cc: Wu Fengguang , LKML , Ingo Molnar , Andi Kleen , Pekka Enberg cc: KAMEZAWA Hiroyuki CC: Nick Piggin CC: Hugh Dickins cc: Linux Memory Management List Subject: [PATCH 8/8] hwpoison: prevent /dev/kcore from accessing hwpoison pages References: <20100113135305.013124116@intel.com> Content-Disposition: inline; filename=hwpoison-kcore.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Silently fill buffer with zeros when encounter hwpoison pages (accessing the hwpoison page content is deadly). This patch does not cover X86_32 - which has a dumb kern_addr_valid(). It is unlikely anyone run a 32bit kernel will care about the hwpoison feature - its usable memory is limited. CC: Ingo Molnar CC: Andi Kleen CC: Pekka Enberg Signed-off-by: Wu Fengguang --- arch/x86/mm/init_64.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- linux-mm.orig/arch/x86/mm/init_64.c 2010-01-13 21:23:04.000000000 +0800 +++ linux-mm/arch/x86/mm/init_64.c 2010-01-13 21:25:32.000000000 +0800 @@ -825,6 +825,7 @@ int __init reserve_bootmem_generic(unsig int kern_addr_valid(unsigned long addr) { unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT; + unsigned long pfn; pgd_t *pgd; pud_t *pud; pmd_t *pmd; @@ -845,14 +846,23 @@ int kern_addr_valid(unsigned long addr) if (pmd_none(*pmd)) return 0; - if (pmd_large(*pmd)) - return pfn_valid(pmd_pfn(*pmd)); + if (pmd_large(*pmd)) { + pfn = pmd_pfn(*pmd); + pfn += pte_index(addr); + goto check_pfn; + } pte = pte_offset_kernel(pmd, addr); if (pte_none(*pte)) return 0; - return pfn_valid(pte_pfn(*pte)); + pfn = pte_pfn(*pte); +check_pfn: + if (!pfn_valid(pfn)) + return 0; + if (PageHWPoison(pfn_to_page(pfn))) + return 0; + return 1; } /*