From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757161AbYAPWY0 (ORCPT ); Wed, 16 Jan 2008 17:24:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754312AbYAPWPl (ORCPT ); Wed, 16 Jan 2008 17:15:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:38282 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753969AbYAPWP1 (ORCPT ); Wed, 16 Jan 2008 17:15:27 -0500 From: Andi Kleen References: <200801161114.239449000@suse.de> In-Reply-To: <200801161114.239449000@suse.de> To: linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, jbeulich@novell.com, venkatesh.pallipadi@intel.com Subject: [PATCH] [26/36] CPA: Dump pagetable when inconsistency is detected Message-Id: <20080116221526.08B80150C8@wotan.suse.de> Date: Wed, 16 Jan 2008 23:15:25 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When c_p_a() detects a inconsistency in the kernel page tables it BUGs. When this happens dump the page table first to avoid one bug reporting round trip. Signed-off-by: Andi Kleen Acked-by: Jan Beulich --- arch/x86/mm/pageattr_32.c | 11 ++++++++++- arch/x86/mm/pageattr_64.c | 11 ++++++++++- 2 files changed, 20 insertions(+), 2 deletions(-) Index: linux/arch/x86/mm/pageattr_64.c =================================================================== --- linux.orig/arch/x86/mm/pageattr_64.c +++ linux/arch/x86/mm/pageattr_64.c @@ -12,6 +12,7 @@ #include #include #include +#include enum flush_mode { FLUSH_NONE, FLUSH_CACHE, FLUSH_TLB }; @@ -231,8 +232,16 @@ __change_page_attr(unsigned long address set_pte(kpte, pfn_pte(pfn, ref_prot)); BUG_ON(page_private(kpte_page) == 0); page_private(kpte_page)--; - } else + } else { + /* + * When you're here you either set the same page to PAGE_KERNEL + * two times in a row or the page table reference counting is + * broken again. To catch the later bug for now (sorry) + */ + printk(KERN_ERR "address %lx\n", address); + dump_pagetable(address); BUG(); + } save_page(kpte_page); if (!PageReserved(kpte_page) && page_private(kpte_page) == 0) Index: linux/arch/x86/mm/pageattr_32.c =================================================================== --- linux.orig/arch/x86/mm/pageattr_32.c +++ linux/arch/x86/mm/pageattr_32.c @@ -13,6 +13,7 @@ #include #include #include +#include #define PG_deferred PG_arch_1 @@ -252,8 +253,16 @@ __change_page_attr(struct page *page, pg set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL)); BUG_ON(page_private(kpte_page) == 0); page_private(kpte_page)--; - } else + } else { + /* + * When you're here you either set the same page to PAGE_KERNEL + * two times in a row or the page table reference counting is + * broken again. To catch the later bug for now (sorry) + */ + printk(KERN_ERR "address %lx\n", address); + dump_pagetable(address); BUG(); + } /* * If the pte was reserved, it means it was created at boot