* Oleg Nesterov <o...@redhat.com> [2012-08-02 16:17:57]:
> Forgot to mention...
>
> On 08/02, Srikar Dronamraju wrote:
> >
> > While at it, add a missing put_uprobe() in the path where uprobe_mmap()
> > races with uprobe_unregister().
> > ...
> > @@ -1051,8 +1051,10 @@ int uprobe_mmap(struct vm_area_struct *vma)
> > if (ret == -EEXIST) {
> > ret = 0;
> >
> > - if (!is_swbp_at_addr(vma->vm_mm, vaddr))
> > + if (!is_swbp_at_addr(vma->vm_mm, vaddr)) {
> > + put_uprobe(uprobe);
> > continue;
> > + }
>
> Yes, this part looks correct.
>
> In fact, I think this is not really correct anyway (wrt counter)
> but we are going to kill it.
>
>
Are you expecting the counter to be decreased/increased here?
This is case where the uprobe_mmap() and uprobe_unregister() raced, and
by the time install_breakpoint() was called by uprobe_mmap(), there were
no consumers. i.e there are no uprobe->consumers and the underlying
instruction is still not a breakpoint instruction.
Since we are refusing to add a breakpoint and that there is no
breakpoint, there is no need to increment/decrement the counter here.
Do let me know if I have missed something.
--
Thanks and Regards
Srikar
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
