Trouble with copyout, memcpy....

[Leunam Elebek]

Hey list,I currently code a driver under Current 8.0 for Current 8.0.But there are some problems with kernel/user-space interaction.I've the following structure:struct daq_kitinfo {        uint32_t ki_maxdata;        uint32_t ki_flags;        uint32_t ki_rng_type;        int           ki_type;        int           ki_nchan;        int           ki_len_chanl;};The above structure is used in my user-space app:int main(void) {        struct daq_kitinfo *info;        struct daq_kit kit;         int fd, size;         ...        ...        ...        /*          * At this point I'll
 try to alloc memory. Notice that          * the size i dependet from another struct entry.         */        size = sizeof(*info) * kit.k_nkits;        info = malloc(size);        if (info == NULL)                exit(ENOMEM);                /*         * The next step is to call the drivers ioctl() interface         * (the reason for that is described below).         */        if (ioctl(fd, DAQ_KITINFO, info)) {                printf("errno: %d\n", errno);                  exit(errno);        }         printf("[ki_nchan] %d\n", ki_nchan);         ...         ...         return (0);}and inside the driver (put it simply):static intmy_ioctl(struct cdev *dev, u_long cmd, caddr_t
 arg, int flags,    struct thread *td){        struct daq_kitinfo *info;        struct daq_kit = dev->si_drv1;         int size;         ...        /* Do something useful e.g mutex'ing... */        ...        /* The same as in user-space... */        size = sizeof(*info) * kit.k_nkits;        info = malloc(sz, M_DAQ, M_NOWAIT | M_ZERO);        if (info == NULL)                ....        /*         * Here I want to copy struct info from kernel to user-space.         * If i use memcpy, the result is that the system hangs         * and I need to reboot the machine. OK, I thought         * copyout() should be able to do the job for me...         */         if (copyout(info, arg, sz))                 /*     
             * Fuc[k-k] i still come inside this block. I always                  * get an EFAULT error.                   */}I really don't know what I should do to let the driver workingproperly. The driver should grap some informations/attributes,and fill up the info structure, so we can copy the filled info structto the user's app.I hope somebody can help me to resolve that problem.Ah, the corresponding ioctl is:#define GRP                        'd'#define DAQ_KITINFO        _IOR(GRP, 3, struct daq_kitinfo)Thanks for attention and greatz from germanyMG