Re: [PATCH v3 2.6.39-rc1-tip 6/26] 6: Uprobes: register/unregister probes.

[Stephen Wilson <wilsons@start.ca>]

On Sat, Apr 02, 2011 at 06:23:53AM +0530, Srikar Dronamraju wrote:
> > > +
> > > +		mm = vma->vm_mm;
> > > +		if (!valid_vma(vma)) {
> > > +			mmput(mm);
> > > +			continue;
> > > +		}
> > > +
> > > +		vaddr = vma->vm_start + offset;
> > > +		vaddr -= vma->vm_pgoff << PAGE_SHIFT;
> > 
> > What happens here when someone passes an offset that is out of bounds
> > for the vma?  Looks like we could oops when the kernel tries to set a
> > breakpoint.  Perhaps check wrt ->vm_end?
> > 
> 
> If the offset is wrong, install_uprobe will fail, since
> grab_cache_page() should not be able to find that page for us.
> And hence we return gracefully.

Hummm.  But grab_cache_page() just wraps find_or_create_page(), so I don't
think it will do what you want.


> I will surely test this case and I am happy to add a check for
> vm_end.

Thanks!


-- 
steve