Re: Slab corruption after unloading a module

[zhiyi huang]

> > There was no problem if I just load and unload the module. But if I
> > write to the device using "ls > /dev/temp" and then unload the
> > module, I would get slab corruption.
>
> you return different value as what has really been consumed:
>
> >         if (*f_pos + count > MAX_DSIZE)
> >                 count1 = MAX_DSIZE - *f_pos;
> >
> >         if (copy_from_user (temp_dev->data+*f_pos, buf, count1)) {
> >                 rv = -EFAULT;
> >                 goto wrap_up;
> >         }
> >         up (&temp_dev->sem);
> >         *f_pos += count1;
> >         return count;
>
> may be it confuses the rest of kernel a bit?

I did this intentionally. Since my baby device buffer is fixed size,  
I can't overflow the buffer. What I do is to cheat the application  
(by pretending the bytes requested are copied to the device) so that  
the application will be happy and do not hang on to send to the  
device again and again. After all it is a test module for char device.
Nevertheless, I don't think this cheating has something to do with  
the slab corruption.
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