[PATCH v3 2.6.39-rc1-tip 15/26] 15: uprobes: Handing int3 and singlestep exception.

[Peter Zijlstra]

On Thu, 2011-04-21 at 22:40 +0530, Srikar Dronamraju wrote:
> * Peter Zijlstra <peterz@infradead.org> [2011-04-19 15:03:05]:
> 
> > On Fri, 2011-04-01 at 20:05 +0530, Srikar Dronamraju wrote:
> > > +       if (unlikely(!utask)) {
> > > +               utask = add_utask();
> > > +
> > > +               /* Failed to allocate utask for the current task. */
> > > +               BUG_ON(!utask);
> > 
> > That's not really nice is it ;-) means I can make the kernel go BUG by
> > simply applying memory pressure.
> > 
> 
> The other option would be remove the probe and set the ip to
> the breakpoint address and restart the thread.

While its better than GFP_NOFAIL since its a return to userspace and
hence cannot be holding locks etc.. it's still not pretty. But heaps
better than simply bailing the kernel.