On Thu, Aug 05, 2021 at 12:00:11AM -0700, longli@xxxxxxxxxxxxxxxxx wrote: > +static int az_blob_create_device(struct az_blob_device *dev) > +{ > + int ret; > + struct dentry *debugfs_root; > + > + dev->misc.minor = MISC_DYNAMIC_MINOR, > + dev->misc.name = "azure_blob", > + dev->misc.fops = &az_blob_client_fops, > + > + ret = misc_register(&dev->misc); > + if (ret) > + return ret; > + > + debugfs_root = debugfs_create_dir("az_blob", NULL); So you try to create a directory in the root of debugfs called "az_blob" for every device in the system of this one type? That will blow up when you have multiple devices of the same type, please fix. thanks, greg k-h