Selon Fawad Lateef <fawadlateef@xxxxxxxxx>:
> On 9/26/05, raja <vnagaraju@xxxxxxxxxxxx> wrote:
> > Hi,
> > I am studying the book LDD3 by rubini.And I am trying to implement
> > the scull char device driver.And I followed the same procedure as in the
> > book.
> > And I implemented only init,exit functions as begining.And I inserted
> > the module.It is inserting fine.And printing the debug messages
> > correctly as i given.
> > But when i try to remove that module,it is comming as segmentation fault
> > and in the kernel log it is printing as
> > Unable to handle kernel NULL pointer dereference at virtual address
> > 00000007
> >
> > I cannot understand where the wrong is.I am listing the code below.Will
> > you please help me.
> >
>
> Compare your code with the example of LDD3 and try to find the problem
> .... You can debug using printk too .... use printk in your exit
> function and try to find the NULL pointer and also can see on which
> line the code is giving fault as you can use printk for before and
> after each line of code or function call and will get prints upto the
> line just above the code which is giving seg fault .....
Hi,
You can try this:
#define DEBUG(fmt, args...) \
printk(KERN_DEBUG "%s:%d:%s(): " fmt "\n", \
__FILE__, __LINE__, __FUNCTION__, ## args)
DEBUG("");
DEBUG("I'm here");
DEBUG("p=%p", p);
Ch'gans
>
> --
> Fawad Lateef
>
> --
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