From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Lalancette Subject: Re: [Fwd: [PATCH]: Fix crash in virtio_blk during modprobe ; rmmod ; modprobe] Date: Thu, 22 May 2008 14:03:07 +0200 Message-ID: <483560FB.4040500@redhat.com> References: <48341FC7.4060600@redhat.com> <200805222133.01686.rusty@rustcorp.com.au> <20080522113517.GC7712@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Rusty Russell , virtualization@lists.linux-foundation.org, kvm@vger.kernel.org To: Jens Axboe Return-path: Received: from mx1.redhat.com ([66.187.233.31]:58777 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756891AbYEVMEv (ORCPT ); Thu, 22 May 2008 08:04:51 -0400 In-Reply-To: <20080522113517.GC7712@kernel.dk> Sender: kvm-owner@vger.kernel.org List-ID: Jens Axboe wrote: > On Thu, May 22 2008, Rusty Russell wrote: >> On Wednesday 21 May 2008 23:12:39 Chris Lalancette wrote: >>> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >>> index 4962e62..c678ac5 100644 >>> --- a/drivers/block/virtio_blk.c >>> +++ b/drivers/block/virtio_blk.c >>> @@ -294,6 +294,7 @@ static void virtblk_remove(struct virtio_device *vdev) >>> vdev->config->reset(vdev); >>> >>> blk_cleanup_queue(vblk->disk->queue); >>> + del_gendisk(vblk->disk); >>> put_disk(vblk->disk); >>> unregister_blkdev(major, "virtblk"); >>> mempool_destroy(vblk->pool); >> Thanks Chris, it seems reasonable and I'm sure it works (kinda hard to >> test here, it's my root block dev). Other drivers seem to do >> blk_cleanup_queue() *after* del_gendisk: does it matter? >> >> Jens CC'd: he's gentle with my dumb questions... Rusty. > > del_gendisk() can generate IO, so it would seem safer to do that > _before_ putting the queue reference :-) > Ah, good to know. Out of curiousity, why would del_gendisk() generate additional I/O? Chris Lalancette