From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030225Ab2HGDxJ (ORCPT ); Mon, 6 Aug 2012 23:53:09 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59641 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757289Ab2HGDiM (ORCPT ); Mon, 6 Aug 2012 23:38:12 -0400 Message-Id: <20120807032756.478538531@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Tue, 07 Aug 2012 04:27:57 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Vivek Goyal , Dirk Gouders , Tejun Heo , Jens Axboe Subject: [ 02/70] floppy: Cleanup disk->queue before caling put_disk() if add_disk() was never called In-Reply-To: <20120807032755.803571133@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vivek Goyal commit 3f9a5aabd0a9fe0e0cd308506f48963d79169aa7 upstream. 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 Signed-off-by: Jens Axboe Signed-off-by: Ben Hutchings --- drivers/block/floppy.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) 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;