On 06.04.2016 09:50, Andy Yan wrote: (...) >>> + return -ENOMEM; >>> + >>> + info->mode = kstrdup_const(prop->name + len, GFP_KERNEL); >>> + if (of_property_read_u32(np, prop->name, &info->magic)) { >>> + dev_err(dev, "reboot mode %s without magic number\n", >>> + info->mode); >>> + devm_kfree(dev, info); >>> + continue; >>> + } >>> + list_add_tail(&info->list, &reboot->head); >>> + } >>> + of_node_put(np); >> If you of_node_put() here, there is no sense in getting it before. I >> mentioned of_node_get() only because I am not sure about life-cycle of >> nodes in case of DT overlays and you are storing the pointer to string >> from DT. >> >> The doubts I have are concerning only the case of freeing nodes from >> overlay. >> >> I don't know if of_node_get() is needed but of_node_get()+of_node_put() >> seems useless. > > > I am also not sure about it. Maybe just drop of_node_get/put ? OK, let's drop both get() and put(). (...) >>> + >>> +static const struct of_device_id syscon_reboot_mode_of_match[] = { >>> + { .compatible = "syscon-reboot-mode" }, >>> + {} >>> +}; >>> + >>> +static struct platform_driver syscon_reboot_mode_driver = { >>> + .probe = syscon_reboot_mode_probe, >> Cleanup needed. What will happen after device unbind? Memory will be >> released (devm-*()) but reboot notifier won't thus leading to OOPS on >> reboot. > > From the kernel_restart_prepare function, the reboot notifier will > be called before device_shutdown. Is there any other case the device > unbind before reboot notifier > called? This is a regular module platform driver so unbind can happen any time initiated by user, either by unbind command or by module removal. User can then re-bind device or not - probably does not matter. Anyway after such first unbind, the restart will kaboom instead of do a restart. Beside that, you always should clean up, regardless of restart or not. If you do not want unbind (thus no need of cleanup) then forbid it by making it a non-module with suppressed bind. Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html