From patchwork Tue Mar 4 11:27:16 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Borntraeger X-Patchwork-Id: 3761301 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2B620BF13A for ; Tue, 4 Mar 2014 11:27:11 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 530E92042B for ; Tue, 4 Mar 2014 11:27:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7470E203B6 for ; Tue, 4 Mar 2014 11:27:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757070AbaCDL1F (ORCPT ); Tue, 4 Mar 2014 06:27:05 -0500 Received: from e06smtp13.uk.ibm.com ([195.75.94.109]:40468 "EHLO e06smtp13.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757069AbaCDL1B (ORCPT ); Tue, 4 Mar 2014 06:27:01 -0500 Received: from /spool/local by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 4 Mar 2014 11:27:00 -0000 Received: from d06dlp01.portsmouth.uk.ibm.com (9.149.20.13) by e06smtp13.uk.ibm.com (192.168.101.143) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 4 Mar 2014 11:26:59 -0000 Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id D93DE17D804E; Tue, 4 Mar 2014 11:27:34 +0000 (GMT) Received: from d06av10.portsmouth.uk.ibm.com (d06av10.portsmouth.uk.ibm.com [9.149.37.251]) by b06cxnps4076.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s24BQkW445744340; Tue, 4 Mar 2014 11:26:46 GMT Received: from d06av10.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av10.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s24BQvvb003305; Tue, 4 Mar 2014 04:26:58 -0700 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d06av10.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s24BQvoS003300; Tue, 4 Mar 2014 04:26:57 -0700 Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 25651) id 9D9F4122443E; Tue, 4 Mar 2014 12:26:57 +0100 (CET) From: Christian Borntraeger To: Paolo Bonzini Cc: Gleb Natapov , KVM , linux-s390 , Cornelia Huck , Martin Schwidefsky , Heinz Graalfs , Thomas Huth , Jens Freimann , Christian Borntraeger Subject: [PULL 6/8] virtio_ccw: fix vcdev pointer handling issues Date: Tue, 4 Mar 2014 12:27:16 +0100 Message-Id: <1393932438-58848-7-git-send-email-borntraeger@de.ibm.com> X-Mailer: git-send-email 1.8.4.2 In-Reply-To: <1393932438-58848-1-git-send-email-borntraeger@de.ibm.com> References: <1393932438-58848-1-git-send-email-borntraeger@de.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14030411-2966-0000-0000-00000A789D16 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Heinz Graalfs The interrupt handler virtio_ccw_int_handler() using the vcdev pointer is protected by the ccw_device lock. Resetting the pointer within the ccw_device structure should be done when holding this lock. Also resetting the vcdev pointer (under the ccw_device lock) prior to freeing the vcdev pointer memory removes a critical path. Signed-off-by: Heinz Graalfs Acked-by: Cornelia Huck Signed-off-by: Christian Borntraeger --- drivers/s390/kvm/virtio_ccw.c | 35 ++++++++++++++++++++++++++++------- 1 file changed, 28 insertions(+), 7 deletions(-) diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index 0fc5848..413c630 100644 --- a/drivers/s390/kvm/virtio_ccw.c +++ b/drivers/s390/kvm/virtio_ccw.c @@ -636,6 +636,8 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev, struct virtqueue *vq; struct virtio_driver *drv; + if (!vcdev) + return; /* Check if it's a notification from the host. */ if ((intparm == 0) && (scsw_stctl(&irb->scsw) == @@ -734,23 +736,37 @@ static int virtio_ccw_probe(struct ccw_device *cdev) return 0; } +static struct virtio_ccw_device *virtio_grab_drvdata(struct ccw_device *cdev) +{ + unsigned long flags; + struct virtio_ccw_device *vcdev; + + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); + vcdev = dev_get_drvdata(&cdev->dev); + if (!vcdev) { + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + return NULL; + } + dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); + return vcdev; +} + static void virtio_ccw_remove(struct ccw_device *cdev) { - struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev); + struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - if (cdev->online) { + if (vcdev && cdev->online) unregister_virtio_device(&vcdev->vdev); - dev_set_drvdata(&cdev->dev, NULL); - } cdev->handler = NULL; } static int virtio_ccw_offline(struct ccw_device *cdev) { - struct virtio_ccw_device *vcdev = dev_get_drvdata(&cdev->dev); + struct virtio_ccw_device *vcdev = virtio_grab_drvdata(cdev); - unregister_virtio_device(&vcdev->vdev); - dev_set_drvdata(&cdev->dev, NULL); + if (vcdev) + unregister_virtio_device(&vcdev->vdev); return 0; } @@ -759,6 +775,7 @@ static int virtio_ccw_online(struct ccw_device *cdev) { int ret; struct virtio_ccw_device *vcdev; + unsigned long flags; vcdev = kzalloc(sizeof(*vcdev), GFP_KERNEL); if (!vcdev) { @@ -786,7 +803,9 @@ static int virtio_ccw_online(struct ccw_device *cdev) INIT_LIST_HEAD(&vcdev->virtqueues); spin_lock_init(&vcdev->lock); + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); dev_set_drvdata(&cdev->dev, vcdev); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); vcdev->vdev.id.vendor = cdev->id.cu_type; vcdev->vdev.id.device = cdev->id.cu_model; ret = register_virtio_device(&vcdev->vdev); @@ -797,7 +816,9 @@ static int virtio_ccw_online(struct ccw_device *cdev) } return 0; out_put: + spin_lock_irqsave(get_ccwdev_lock(cdev), flags); dev_set_drvdata(&cdev->dev, NULL); + spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags); put_device(&vcdev->vdev.dev); return ret; out_free: