I'll guess that what put_user is being asked to copy isn't an
appropriate size. copy_to_user() allows the movement of chunks of
data that aren't 1, 2, or 4 bytes in size.
BTW, I found put_user in include/linux/asm/uaccess.h (asm -> asmi386
in my case)
-Richard
Elena Lazkano Ortega wrote:
>
> Hello,
>
> I'm trying to understand how Linux modules work basically reading a
> documentation I got in Internet which has some gradually increasing
> complexity examples. The examples are about how to communicate with a
> character device and they use a function named "put_user" (to put the
> message
> in the kernel address space in the user address space).
> When I try to insert the module using this function I get an error message
> like
> "bad_user_access_length" that I believe comes from a file called
> "panic.c".
>
> I know that the function is a macro defined in the file "segment.h" but I
> don't know exactly how it works.
> Can somebody help me or give a little explanation or some reference books
> that I could use?
>
> Thans in advance!
>
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--
Richard Dynes
rdynes@varcom.com
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