Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754365Ab0LLXpq (ORCPT ); Sun, 12 Dec 2010 18:45:46 -0500 Received: from one.firstfloor.org ([213.235.205.2]:44551 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752808Ab0LLXo6 (ORCPT ); Sun, 12 Dec 2010 18:44:58 -0500 From: Andi Kleen References: <201012131244.547034648@firstfloor.org> In-Reply-To: <201012131244.547034648@firstfloor.org> To: jack@suse.cz, jaxboe@fusionio.com, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org Subject: [PATCH] [2/223] block: Fix race during disk initialization Message-Id: <20101212234456.CB45FB27BF@basil.firstfloor.org> Date: Mon, 13 Dec 2010 00:44:56 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2017 Lines: 55 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit 01ea50638bc04ca5259f5711fcdedefcdde1cf43 upstream. When a new disk is being discovered, add_disk() first ties the bdev to gendisk (via register_disk()->blkdev_get()) and only after that calls bdi_register_bdev(). Because register_disk() also creates disk's kobject, it can happen that userspace manages to open and modify the device's data (or inode) before its BDI is properly initialized leading to a warning in __mark_inode_dirty(). Fix the problem by registering BDI early enough. This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=16312 Reported-by: Larry Finger Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- block/genhd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) Index: linux/block/genhd.c =================================================================== --- linux.orig/block/genhd.c +++ linux/block/genhd.c @@ -541,13 +541,15 @@ void add_disk(struct gendisk *disk) disk->major = MAJOR(devt); disk->first_minor = MINOR(devt); + /* Register BDI before referencing it from bdev */ + bdi = &disk->queue->backing_dev_info; + bdi_register_dev(bdi, disk_devt(disk)); + blk_register_region(disk_devt(disk), disk->minors, NULL, exact_match, exact_lock, disk); register_disk(disk); blk_register_queue(disk); - bdi = &disk->queue->backing_dev_info; - bdi_register_dev(bdi, disk_devt(disk)); retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj, "bdi"); WARN_ON(retval); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/