From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750730AbWDQMui (ORCPT ); Mon, 17 Apr 2006 08:50:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750773AbWDQMui (ORCPT ); Mon, 17 Apr 2006 08:50:38 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:4002 "EHLO ogre.sisk.pl") by vger.kernel.org with ESMTP id S1750730AbWDQMuh (ORCPT ); Mon, 17 Apr 2006 08:50:37 -0400 From: "Rafael J. Wysocki" To: Andrew Morton Subject: [PATCH][urgent fix] swsusp: prevent possible image corruption on resume Date: Mon, 17 Apr 2006 14:49:23 +0200 User-Agent: KMail/1.9.1 Cc: LKML , Pavel Machek , Adrian Bunk MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604171449.24548.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The function free_pagedir() used by swsusp for freeing its internal data structures clears the PG_nosave and PG_nosave_free flags for each page being freed. However, during resume PG_nosave_free set means that the page in question is "unsafe" (ie. it will be overwritten in the process of restoring the saved system state from the image), so it should not be used for the image data. Therefore free_pagedir() should not clear PG_nosave_free if it's called during resume (otherwise "unsafe" pages freed by it may be used for storing the image data and the data may get corrupted later on). Signed-off-by: Rafael J. Wysocki --- kernel/power/snapshot.c | 9 +++++---- 1 files changed, 5 insertions(+), 4 deletions(-) Index: linux-2.6.17-rc1-mm2/kernel/power/snapshot.c =================================================================== --- linux-2.6.17-rc1-mm2.orig/kernel/power/snapshot.c 2006-04-17 13:47:58.000000000 +0200 +++ linux-2.6.17-rc1-mm2/kernel/power/snapshot.c 2006-04-17 13:50:34.000000000 +0200 @@ -240,14 +240,15 @@ static void copy_data_pages(struct pbe * * free_pagedir - free pages allocated with alloc_pagedir() */ -static void free_pagedir(struct pbe *pblist) +static void free_pagedir(struct pbe *pblist, int clear_nosave_free) { struct pbe *pbe; while (pblist) { pbe = (pblist + PB_PAGE_SKIP)->next; ClearPageNosave(virt_to_page(pblist)); - ClearPageNosaveFree(virt_to_page(pblist)); + if (clear_nosave_free) + ClearPageNosaveFree(virt_to_page(pblist)); free_page((unsigned long)pblist); pblist = pbe; } @@ -389,7 +390,7 @@ struct pbe *alloc_pagedir(unsigned int n pbe->next = alloc_image_page(gfp_mask, safe_needed); } if (!pbe) { /* get_zeroed_page() failed */ - free_pagedir(pblist); + free_pagedir(pblist, 1); pblist = NULL; } else create_pbe_list(pblist, nr_pages); @@ -736,7 +737,7 @@ static int create_image(struct snapshot_ pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1); if (pblist) copy_page_backup_list(pblist, p); - free_pagedir(p); + free_pagedir(p, 0); if (!pblist) error = -ENOMEM; }