Hi Deepak, On Thu, Jan 27, 2022 at 12:34:44AM +0530, Deepak Kumar Singh wrote: > Struct device holding cdev should not be freed unless cdev > is not in use. It is possible that user space has opened > char device while kernel has freed the associated struct > device context. > > Mark dev kobj as parent of cdev, so that chardev_add gets > an extra reference to dev. This ensures device context is not > freed until cdev is is not in uses. > --- > drivers/rpmsg/rpmsg_char.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index c03a118..72ee101 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -417,6 +417,7 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, > dev->id = ret; > dev_set_name(dev, "rpmsg%d", ret); > > + cdev_set_parent(&eptdev->cdev, &dev->kobj); > ret = cdev_add(&eptdev->cdev, dev->devt, 1); This issue should have been fixed when cdev_add() was replaced by cdev_device_add(), something you will find on v5.17-rc2. Also, this set is generating checkpatch warnings and as such I will not review the other patches in it. Thanks, Mathieu > if (ret) > goto free_ept_ida; > @@ -533,6 +534,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) > dev->id = ret; > dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret); > > + cdev_set_parent(&ctrldev->cdev, &dev->kobj); > ret = cdev_add(&ctrldev->cdev, dev->devt, 1); > if (ret) > goto free_ctrl_ida; > -- > 2.7.4 >
