From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753740Ab2A3PAM (ORCPT ); Mon, 30 Jan 2012 10:00:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54327 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753352Ab2A3PAK (ORCPT ); Mon, 30 Jan 2012 10:00:10 -0500 From: Vivek Goyal To: linux-kernel@vger.kernel.org, axboe@kernel.dk Cc: tj@kernel.org, sjayaraman@suse.com, gouders@et.bocholt.fh-gelsenkirchen.de, vgoyal@redhat.com Subject: [PATCH 1/2] floppy: Cleanup disk->queue before caling put_disk() if add_disk() was never called Date: Mon, 30 Jan 2012 09:59:50 -0500 Message-Id: <1327935591-26812-2-git-send-email-vgoyal@redhat.com> In-Reply-To: <1327935591-26812-1-git-send-email-vgoyal@redhat.com> References: <1327935591-26812-1-git-send-email-vgoyal@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org add_disk() takes gendisk reference on request queue. If driver failed during initialization and never called add_disk() then that extra reference is not taken. That reference is put in put_disk(). floppy driver allocates the disk, allocates queue, sets disk->queue and then relizes that floppy controller is not present. It tries to tear down everything and tries to put a reference down in put_disk() which was never taken. In such error cases cleanup disk->queue before calling put_disk() so that we never try to put down a reference which was never taken in first place. Reported-and-tested-by: Suresh Jayaraman Tested-by: Dirk Gouders Signed-off-by: Vivek Goyal Acked-by: Tejun Heo --- drivers/block/floppy.c | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 510fb10..401ba78 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4368,8 +4368,14 @@ out_unreg_blkdev: out_put_disk: while (dr--) { del_timer_sync(&motor_off_timer[dr]); - if (disks[dr]->queue) + if (disks[dr]->queue) { blk_cleanup_queue(disks[dr]->queue); + /* + * put_disk() is not paired with add_disk() and + * will put queue reference one extra time. fix it. + */ + disks[dr]->queue = NULL; + } put_disk(disks[dr]); } return err; -- 1.7.4.4