On Thu, 2005-06-02 at 19:25 +0530, Gaurav Dhiman wrote:
> >
> > asmlinkage long our_sys_unlink(const char *filename )
> > {
> > printk("File is about to get deleted " ); /* print a message when
> a file is to be
> > deleted*/
> > printk("%s",filename);
>
> You should not do this, as file name is the pointer to user memory and
> user memory can any time be swaped out, so you first do copy the
> filename from user buffer to kernel buffer using copy_from_user
> function and then pass the pointer to your kernel buffer to printk()
Even if it IS swapped out, accessing that pointer is going to cause
a page fault. In this case the fxn. will be put to sleep while the
kernel handles the page fault....so if the fxn. doesn't have a problem
sleeping...then it should be OK! But strictly speaking this is NOT a
recommended practice.
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