Re: [PATCH v1 4/10] User Space Breakpoint Assistance Layer

[Srikar Dronamraju <srikar@linux.vnet.ibm.com>]

> 
> > User Space Breakpoint Assistance Layer (USER_BKPT)
> > 
> 
> A quick scan, just to show I was paying attention ;)

Thanks for taking a look and commenting on the code.

> 
> > +int user_bkpt_read_vm(struct task_struct *tsk, unsigned long vaddr,
> > +						void *kbuf, int nbytes)
> > +{
> > +	if (tsk == current) {
> > +		int nleft = copy_from_user(kbuf, (void __user *) vaddr,
> > +				nbytes);
> > +		return nbytes - nleft;
> > +	} else
> > +		return access_process_vm(tsk, vaddr, kbuf, nbytes, 0);
> > +}
> 
> copy_from_user() takes and returns an unsigned long arg but this
> function is converting these to and from ints.  That's OK if we're 100%
> sure that we'll never get or return an arg >2G.  Otherwise things could
> get ghastly.  Please have a think.  (Dittoes for some other functionss
> around here).
> 

nbytes would not be greater than the maximum size of a instruction for
that architecture. Hence I dont see it going above 2G. However I will
take a relook.


I will rework the rest of the comments as suggested by you.
It would be part of the next version.

--
Thanks and Regards
Srikar