> From: Zhao, Yan Y <yan.y.zhao@xxxxxxxxx> > Sent: Thursday, February 16, 2023 4:24 PM > > On Mon, Feb 13, 2023 at 07:13:47AM -0800, Yi Liu wrote: > ... > > > +long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, > > + unsigned long arg) > > +{ > > + struct vfio_device *device = df->device; > > + struct vfio_device_bind_iommufd bind; > > + struct iommufd_ctx *iommufd = NULL; > > + struct fd f; > > + unsigned long minsz; > > + int ret; > > + > > + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); > > + > > + if (copy_from_user(&bind, (void __user *)arg, minsz)) > > + return -EFAULT; > > + > > + if (bind.argsz < minsz || bind.flags) > > + return -EINVAL; > > + > > + if (!device->ops->bind_iommufd) > > + return -ENODEV; > > + > > + ret = vfio_device_claim_group(device); > > + if (ret) > > + return ret; > > + > > + mutex_lock(&device->dev_set->lock); > > + /* > > + * If already been bound to an iommufd, or already set noiommu > > + * then fail it. > > + */ > > + if (df->iommufd || df->noiommu) { > > + ret = -EINVAL; > > + goto out_unlock; > > + } > > + > > + /* iommufd < 0 means noiommu mode */ > > + if (bind.iommufd < 0) { > > + if (!capable(CAP_SYS_RAWIO)) { > > + ret = -EPERM; > > + goto out_unlock; > > + } > > + df->noiommu = true; > > + } else { > > + f = fdget(bind.iommufd); > Here, the iommufd file count + 1, > > > + if (!f.file) { > > + ret = -EBADF; > > + goto out_unlock; > > + } > > + iommufd = iommufd_ctx_from_file(f.file); > iommufd file count + 1, again > > > + if (IS_ERR(iommufd)) { > > + ret = PTR_ERR(iommufd); > > + goto out_put_file; > > + } > > + } > > + > > + /* > > + * Before the device open, get the KVM pointer currently > > + * associated with the device file (if there is) and obtain a > > + * reference. This reference is held until device closed. Save > > + * the pointer in the device for use by drivers. > > + */ > > + vfio_device_get_kvm_safe(df); > > + > > + df->iommufd = iommufd; > > + ret = vfio_device_open(df, &bind.out_devid, NULL); > iommufd file count + 1 in iommufd_device_bind for first open. > > > + if (ret) > > + goto out_put_kvm; > > + > > + ret = copy_to_user((void __user *)arg + > > + offsetofend(struct vfio_device_bind_iommufd, > iommufd), > > + &bind.out_devid, > > + sizeof(bind.out_devid)) ? -EFAULT : 0; > > + if (ret) > > + goto out_close_device; > > + > > + if (iommufd) > > + fdput(f); > But, only one file count is put. Good catch! Yes it is missed. And needs to call iommufd_ctx_put() in vfio_device_cdev_close() as well. > Need a paring iommufd_ctx_put() after a successful > iommufd_ctx_from_file() > above to avoid iommufd_fops_release() never being called. > > e.g. > > @@ -1222,11 +1226,13 @@ static long > vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df, > ret = -EBADF; > goto out_unlock; > } > iommufd = iommufd_ctx_from_file(f.file); > if (IS_ERR(iommufd)) { > ret = PTR_ERR(iommufd); > goto out_put_file; > } > + iommufd_ctx_put(iommufd); Since iommufd is recorded in df, so needs to hold refcount till df->iommufd=NULL; Thanks, Yi Liu > } > > /* df->kvm is supposed to be set in vfio_device_file_set_kvm() */ > > > + else if (df->noiommu) > > + dev_warn(device->dev, "vfio-noiommu device used by user > " > > + "(%s:%d)\n", current->comm, > task_pid_nr(current)); > > + mutex_unlock(&device->dev_set->lock); > > + return 0; > > + > > +out_close_device: > > + vfio_device_close(df); > > +out_put_kvm: > > + df->iommufd = NULL; > > + df->noiommu = false; > > + vfio_device_put_kvm(device); > > +out_put_file: > > + if (iommufd) > > + fdput(f); > > +out_unlock: > > + mutex_unlock(&device->dev_set->lock); > > + vfio_device_release_group(device); > > + return ret; > > +} > > +