On Fri, Jan 23, 2004 at 01:37:53 -0800, prasanna wakhare wrote:
> Hi all,
> After resolving lots of unresolved symbol i finally
> load the very simple sculldevice driver
>
> but when i perform
> cp /dev/zero /dev/scull0
>
> my system is getting hang!
That can be absolutely anything. You need to say what exactly does it
mean "hang" and probably also code for the module (the open and write
functions are important).
Also, first try:
: > /dev/scull0
(open + close, but no write at all)
echo "foo" > /dev/scull0
(ie. write of limited number of bytes)
That should narrow down the problem to either open (or close) or write
function. (cp /dev/zero /dev/scull0 will run for indefinite time (since
there are always zeroes to be read from /dev/zero))
Notes:
- Check your locking (rules are described in Documentation/locking
or somesuch).
- Check your refcounting (miscounts tend to result in very
unpredictable behaviour).
- Put a lot of printks in your driver so you know WHEN it hangs.
> the same with if anybody has compiled the faulty
> module from Rubini's book
What version was the module written for and what kernel version did you
try it on.
-------------------------------------------------------------------------------
Jan 'Bulb' Hudec <bulb@ucw.cz>
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