From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kirti Wankhede Subject: Re: [PATCH 1/8] vfio/mdev: Fix to not do put_device on device_register failure Date: Mon, 25 Mar 2019 23:47:30 +0530 Message-ID: <2c096714-74cd-48ff-496f-b3919990e3e5@nvidia.com> References: <1553296835-37522-1-git-send-email-parav@mellanox.com> <1553296835-37522-2-git-send-email-parav@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: Parav Pandit , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "alex.williamson@redhat.com" Return-path: In-Reply-To: <1553296835-37522-2-git-send-email-parav@mellanox.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 3/23/2019 4:50 AM, Parav Pandit wrote: > device_register() performs put_device() if device_add() fails. > This balances with device_initialize(). > > mdev core performing put_device() when device_register() fails, > is an error that puts already released device again. > Therefore, don't put the device on error. > device_add() on all errors doesn't call put_device(dev). It releases reference to its parent, put_device(parent), but not the device itself, put_device(dev). Thanks, Kirti > Fixes: 7b96953bc640 ("vfio: Mediated device Core driver") > Signed-off-by: Parav Pandit > --- > drivers/vfio/mdev/mdev_core.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c > index 0212f0e..3e5880a 100644 > --- a/drivers/vfio/mdev/mdev_core.c > +++ b/drivers/vfio/mdev/mdev_core.c > @@ -318,10 +318,8 @@ int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid) > dev_set_name(&mdev->dev, "%pUl", uuid.b); > > ret = device_register(&mdev->dev); > - if (ret) { > - put_device(&mdev->dev); > + if (ret) > goto mdev_fail; > - } > > ret = mdev_device_create_ops(kobj, mdev); > if (ret) >