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, "Michael S. Tsirkin" , Rusty Russell Subject: [PATCH 3.19 19/75] virtio_balloon: set DRIVER_OK before using device Date: Fri, 10 Apr 2015 15:18:45 +0200 Message-Id: <20150410131708.919441582@linuxfoundation.org> In-Reply-To: <20150410131707.794709951@linuxfoundation.org> References: <20150410131707.794709951@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" commit 88660f7fb94cda1f8f63ee92bfcd0db39a6361e2 upstream. virtio spec requires that all drivers set DRIVER_OK before using devices. While balloon isn't yet included in the virtio 1 spec, previous spec versions also required this. virtio balloon might violate this rule: probe calls kthread_run before setting DRIVER_OK, which might run immediately and cause balloon to inflate/deflate. To fix, call virtio_device_ready before running the kthread. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Signed-off-by: Greg Kroah-Hartman --- drivers/virtio/virtio_balloon.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -494,6 +494,8 @@ static int virtballoon_probe(struct virt if (err < 0) goto out_oom_notify; + virtio_device_ready(vdev); + vb->thread = kthread_run(balloon, vb, "vballoon"); if (IS_ERR(vb->thread)) { err = PTR_ERR(vb->thread);