Simple Misc Driver - Problem with string copy to user

[Le Tan]

I think it is good for you to read LDD3 or google some corresponding
materials at first.

2014-05-27 20:48 GMT+08:00 Lucas Tanure <tanure at linux.com>:
> Hi!
>
> Goal, when the user do :
> # head -1 /dev/miscdrv
>
> The driver prints:  Hello World!
>
> Steps:
> # Make
> # insmod misc.ko
> # head -1 /dev/miscdrv
>
> Why my driver doesn't work ?
>
> What is worg with my read operation?
>
> static ssize_t
> misc_drv_read(struct file *filp, char __user * buf, size_t count, loff_t *
> offp){
>     int nbytes;
> char * string = "hello World";
> nbytes = copy_to_user(buf, string, 12);
> return nbytes;
> }
>
>
> --
> Lucas Tanure
> Brazil
>
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