From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755445Ab2HNJDw (ORCPT ); Tue, 14 Aug 2012 05:03:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40325 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755213Ab2HNJDv (ORCPT ); Tue, 14 Aug 2012 05:03:51 -0400 Date: Tue, 14 Aug 2012 11:03:30 +0200 From: Stanislaw Gruszka To: Ben Hutchings Cc: Herton Ronaldo Krzesinski , Jens Axboe , Jiri Kosina , Andrew Morton , Tejun Heo , linux-kernel@vger.kernel.org, Vivek Goyal Subject: Re: [PATCH v3 3/6] floppy: avoid leaking extra reference to queue on do_floppy_init error handling Message-ID: <20120814090330.GC2423@redhat.com> References: <1344881787-6422-1-git-send-email-herton.krzesinski@canonical.com> <1344881787-6422-4-git-send-email-herton.krzesinski@canonical.com> <1344914439.824.178.camel@deadeye.wl.decadent.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1344914439.824.178.camel@deadeye.wl.decadent.org.uk> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 14, 2012 at 04:20:39AM +0100, Ben Hutchings wrote: > On Mon, 2012-08-13 at 15:16 -0300, Herton Ronaldo Krzesinski wrote: > > After commit 3f9a5aa ("floppy: Cleanup disk->queue before caling > > put_disk() if add_disk() was never called"), if something fails in the > > add_disk loop, we unconditionally set disks[dr]->queue to NULL. But > > that's wrong, since we may have succesfully done an add_disk on some of > > the drives previously in the loop, and in this case we would end up with > > an extra reference to the disks[dr]->queue. > > > > Add a new global array to mark "registered" disks, and use that to check > > if we did an add_disk on one of the disks already. Using an array to > > track added disks also will help to simplify/cleanup code later, as > > suggested by Vivek Goyal. > [...] > > It's totally ridiculous that a driver should have to do this. Any > registered disk should have the GENHD_FL_UP flag set... so why can't > genhd check it? It doesn't look like floppy is the only driver affected > by this problem, either. So I suggest the following general fix > (untested): > > --- > Subject: genhd: Make put_disk() safe for disks that have not been registered > > Since commit 9f53d2f ('block: fix __blkdev_get and add_disk race > condition'), add_disk() adds a reference to disk->queue, I do not see this? Commit 9f53d2fe insert disk_alloc_events() to add_disk(), but disk_alloc_events() function does not get any reference to disk->queue, I missed something? Stanislaw