On Tue, Jan 09, 2018 at 02:31:23PM -0800, Jae Hyun Yoo wrote: > +#pragma pack(push, 1) > +struct peci_xfer_msg { > + unsigned char client_addr; > + unsigned char tx_len; > + unsigned char rx_len; > + unsigned char tx_buf[MAX_BUFFER_SIZE]; > + unsigned char rx_buf[MAX_BUFFER_SIZE]; > +}; > +#pragma pack(pop) For any structure that crosses the user/kernel boundry, you _HAVE_ to use the "__" variant. So for here you would use __u8 instead of "unsigned char" in order for things to work properly. I'm guessing you didn't test this all out on a mixed 32/64 bit system? Please fix up and test to ensure that it all works properly before resubmitting. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html