From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756698Ab3LBUBe (ORCPT ); Mon, 2 Dec 2013 15:01:34 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:39204 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754641Ab3LBTR6 (ORCPT ); Mon, 2 Dec 2013 14:17:58 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Oliver Lorenz , "Rafael J. Wysocki" Subject: [PATCH 3.12 098/212] PM / Hibernate: Do not crash kernel in free_basic_memory_bitmaps() Date: Mon, 2 Dec 2013 11:14:49 -0800 Message-Id: <20131202191258.369635385@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.3.gca3854a In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> User-Agent: quilt/0.60-8.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Rafael J. Wysocki" commit 6a0c7cd33075f6b7f1d80145bb19812beb3fc5c9 upstream. I have received a report about the BUG_ON() in free_basic_memory_bitmaps() triggering mysteriously during an aborted s2disk hibernation attempt. The only way I can explain that is that /dev/snapshot was first opened for writing (resume mode), then closed and then opened again for reading and closed again without freezing tasks. In that case the first invocation of snapshot_open() would set the free_bitmaps flag in snapshot_state, which is a static variable. That flag wouldn't be cleared later and the second invocation of snapshot_open() would just leave it like that, so the subsequent snapshot_release() would see data->frozen set and free_basic_memory_bitmaps() would be called unnecessarily. To prevent that from happening clear data->free_bitmaps in snapshot_open() when the file is being opened for reading (hibernate mode). In addition to that, replace the BUG_ON() in free_basic_memory_bitmaps() with a WARN_ON() as the kernel can continue just fine if the condition checked by that macro occurs. Fixes: aab172891542 (PM / hibernate: Fix user space driven resume regression) Reported-by: Oliver Lorenz Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- kernel/power/snapshot.c | 3 ++- kernel/power/user.c | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -792,7 +792,8 @@ void free_basic_memory_bitmaps(void) { struct memory_bitmap *bm1, *bm2; - BUG_ON(!(forbidden_pages_map && free_pages_map)); + if (WARN_ON(!(forbidden_pages_map && free_pages_map))) + return; bm1 = forbidden_pages_map; bm2 = free_pages_map; --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -70,6 +70,7 @@ static int snapshot_open(struct inode *i data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device, 0, NULL) : -1; data->mode = O_RDONLY; + data->free_bitmaps = false; error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE); if (error) pm_notifier_call_chain(PM_POST_HIBERNATION);