From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Josef Bacik , Jens Axboe Subject: [PATCH 4.14 34/52] nbd: fix nbd device deletion Date: Sun, 24 Jun 2018 23:21:27 +0800 Message-Id: <20180624142746.508838594@linuxfoundation.org> In-Reply-To: <20180624142744.234164867@linuxfoundation.org> References: <20180624142744.234164867@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik commit 8364da4751cf22201d74933d5e634176f44ed407 upstream. This fixes a use after free bug, we shouldn't be doing disk->queue right after we do del_gendisk(disk). Save the queue and do the cleanup after the del_gendisk. Fixes: c6a4759ea0c9 ("nbd: add device refcounting") cc: stable@vger.kernel.org Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/block/nbd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -173,9 +173,12 @@ static const struct device_attribute pid static void nbd_dev_remove(struct nbd_device *nbd) { struct gendisk *disk = nbd->disk; + struct request_queue *q; + if (disk) { + q = disk->queue; del_gendisk(disk); - blk_cleanup_queue(disk->queue); + blk_cleanup_queue(q); blk_mq_free_tag_set(&nbd->tag_set); disk->private_data = NULL; put_disk(disk);