On Tue, Dec 15, 2020 at 08:55:57PM +0100, javier@xxxxxxxxxxx wrote: > +static int nvme_alloc_chardev_ns(struct nvme_ctrl *ctrl, struct nvme_ns *ns) > +{ > + char cdisk_name[DISK_NAME_LEN]; > + int ret; > + > + device_initialize(&ns->cdev_device); > + ns->cdev_device.devt = MKDEV(MAJOR(nvme_ns_base_chr_devt), > + ns->head->instance); Ah, I see now. We are making these generic handles for each path, but the ns->head->instance is the same for all paths to a namespace, so it's not unique for that. Further, that head->instance is allocated per subsystem, so it's not unique from namespace heads seen in other subsystems. So, I think you need to allocate a new dev_t for each subsystem rather than the global nvme_ns_base_chr_devt, and I guess we also need a new nvme_ns instance field assigned from yet another ida?