From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757085AbZBFCCU (ORCPT ); Thu, 5 Feb 2009 21:02:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753071AbZBFCCN (ORCPT ); Thu, 5 Feb 2009 21:02:13 -0500 Received: from smtp-outbound-1.vmware.com ([65.115.85.69]:44404 "EHLO smtp-outbound-1.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752288AbZBFCCM (ORCPT ); Thu, 5 Feb 2009 21:02:12 -0500 Subject: [PARAVIRT/x86] BUGFIX: Put a missing paravirt_release_pmd in pgd_dtor From: Alok Kataria Reply-To: akataria@vmware.com To: Ingo Molnar , "H. Peter Anvin" , the arch/x86 maintainers Cc: Jeremy Fitzhardinge , Zachary Amsden , Rusty Russell , Rohit Jain , LKML Content-Type: text/plain Organization: VMware INC. Date: Thu, 05 Feb 2009 18:02:11 -0800 Message-Id: <1233885731.29693.26.camel@alok-dev1> Mime-Version: 1.0 X-Mailer: Evolution 2.8.0 (2.8.0-40.el5_1.1) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [PARAVIRT/x86] Put a missing paravirt_release_pmd in pgd_dtor. From: Alok N Kataria The commit... ----------------------------- commit 6194ba6ff6ccf8d5c54c857600843c67aa82c407 Author: Jeremy Fitzhardinge Date: Wed Jan 30 13:34:11 2008 +0100 x86: don't special-case pmd allocations as much ------------------------------ ...made changes to the way we handle pmd allocations, and while doing that it (accidently ?) dropped a call to paravirt_release_pd from the pgd_dtor code path. As a result of this missing release, the hypervisor is now unaware of the pgd page being freed, and as a result it ends up tracking this page as a page table page. After this the guest may start using the same page for other purposes, and depending on what use the page is put to, it may result in various performance and/or functional issues ( hangs, reboots). The patch below adds a paravirt_release_pmd call for the PGD page. Patch on top of 2.6.29-rc3 (mainline-git). Signed-off-by: Alok N Kataria Signed-off-by: Rohit Jain Cc: Zachary Amsden Cc: Jeremy Fitzhardinge Cc: stable@kernel.org --- arch/x86/mm/pgtable.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 86f2ffc..c23cd7e 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -89,6 +89,12 @@ static void pgd_dtor(pgd_t *pgd) { unsigned long flags; /* can be called from interrupt context */ + if (PAGETABLE_LEVELS == 2 || + (PAGETABLE_LEVELS == 3 && SHARED_KERNEL_PMD) || + PAGETABLE_LEVELS == 4) { + paravirt_release_pmd(__pa(pgd) >> PAGE_SHIFT); + } + if (SHARED_KERNEL_PMD) return;