From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757349AbZCAOLY (ORCPT ); Sun, 1 Mar 2009 09:11:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754468AbZCAOLP (ORCPT ); Sun, 1 Mar 2009 09:11:15 -0500 Received: from ey-out-2122.google.com ([74.125.78.26]:1803 "EHLO ey-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754390AbZCAOLO convert rfc822-to-8bit (ORCPT ); Sun, 1 Mar 2009 09:11:14 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:in-reply-to:references :x-mailer:mime-version:content-type:content-transfer-encoding; b=lFOvxYyKtLhz/gNQXeAHt6Ri9FXjsy54cTUZFWbjxTlSsM8GYaNtSoL4Ifiv+ibFWb dVgXjhSSxHaJVthRx521p4ScqKfyNfiarL9GE6bkQ2FiG0jOVIMNApbKVS/SC6ATe3IS CpcDuMoeapHGlDy4lx9YcfBhtcoeQw1UXvW3A= Date: Sun, 1 Mar 2009 16:11:07 +0200 From: Pekka Paalanen To: Steven Rostedt , Ingo Molnar Cc: Pekka Paalanen , Stuart Bennett , "linux-kernel@vger.kernel.org" Subject: [PATCH 3/7] x86 mmiotrace: WARN_ONCE if dis/arming a page fails Message-ID: <20090301161107.21d82c10@daedalus.pq.iki.fi> In-Reply-To: <20090301160643.05a2219b@daedalus.pq.iki.fi> References: <20090301160643.05a2219b@daedalus.pq.iki.fi> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.12.11; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From 2f1f600e019955a0485452e4da676837bc8c91bd Mon Sep 17 00:00:00 2001 From: Stuart Bennett Date: Fri, 30 Jan 2009 17:38:59 +0000 Subject: [PATCH] x86 mmiotrace: WARN_ONCE if dis/arming a page fails Print a full warning once, if arming or disarming a page fails. Also, if initial arming fails, do not handle the page further. This avoids the possibility of a page failing to arm and then later claiming to have handled any fault on that page. WARN_ONCE added by Pekka Paalanen. Signed-off-by: Stuart Bennett Signed-off-by: Pekka Paalanen --- arch/x86/mm/kmmio.c | 25 +++++++++++++++++-------- 1 files changed, 17 insertions(+), 8 deletions(-) diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c index 93d8203..fb1f115 100644 --- a/arch/x86/mm/kmmio.c +++ b/arch/x86/mm/kmmio.c @@ -105,7 +105,7 @@ static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long page) return NULL; } -static void set_page_present(unsigned long addr, bool present, +static int set_page_present(unsigned long addr, bool present, unsigned int *pglevel) { pteval_t pteval; @@ -116,7 +116,7 @@ static void set_page_present(unsigned long addr, bool present, if (!pte) { pr_err("kmmio: no pte for page 0x%08lx\n", addr); - return; + return -1; } if (pglevel) @@ -140,22 +140,27 @@ static void set_page_present(unsigned long addr, bool present, default: pr_err("kmmio: unexpected page level 0x%x.\n", level); - return; + return -1; } __flush_tlb_one(addr); + + return 0; } /** Mark the given page as not present. Access to it will trigger a fault. */ -static void arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel) +static int arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel) { - set_page_present(page & PAGE_MASK, false, pglevel); + int ret = set_page_present(page & PAGE_MASK, false, pglevel); + WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", page); + return ret; } /** Mark the given page as present. */ static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel) { - set_page_present(page & PAGE_MASK, true, pglevel); + int ret = set_page_present(page & PAGE_MASK, true, pglevel); + WARN_ONCE(ret < 0, KERN_ERR "kmmio disarming 0x%08lx failed.\n", page); } /* @@ -326,9 +331,13 @@ static int add_kmmio_fault_page(unsigned long page) f->count = 1; f->page = page; - list_add_rcu(&f->list, kmmio_page_list(f->page)); - arm_kmmio_fault_page(f->page, NULL); + if (arm_kmmio_fault_page(f->page, NULL)) { + kfree(f); + return -1; + } + + list_add_rcu(&f->list, kmmio_page_list(f->page)); return 0; } -- 1.6.0.6