On Thu, May 17, 2018 at 07:03:30PM +0200, Guido Kiener wrote: > +/* > + * usbtmc_message->flags: > + */ > +#define USBTMC_FLAG_ASYNC 0x0001 > +#define USBTMC_FLAG_APPEND 0x0002 > +#define USBTMC_FLAG_IGNORE_TRAILER 0x0004 > + > +struct usbtmc_message { > + void __user *message; /* pointer to header and data */ > + __u64 transfer_size; /* size of bytes to transfer */ > + __u64 transferred; /* size of received/written bytes */ > + __u32 flags; /* bit 0: 0 = synchronous; 1 = asynchronous */ > +} __attribute__ ((packed)); Very odd structure. Your userspace pointer is going to be totally out of alignment on 32bit systems running on a 64bit kernel. Why have a separate pointer at all? Why not just put the mesage at the end of this structure directly with something like: __u8 message[0]; ? Much easier and you don't have to mess with the whole compatible ioctl thunking layer (which I think you ignored here, which means you all didn't test it...) thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html