Re: perf_fuzzer compiled for x32 causes reboot

[Steven Rostedt]

On Fri, 28 Feb 2014 22:55:11 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Fri, Feb 28, 2014 at 01:51:50PM -0800, Paul E. McKenney wrote:
> > On Fri, Feb 28, 2014 at 10:27:00PM +0100, Peter Zijlstra wrote:
> > > On Fri, Feb 28, 2014 at 01:17:33PM -0800, Paul E. McKenney wrote:
> > > > This code isn't running in idle context is it?  If so, RCU will happily
> > > > free out from under it.  CONFIG_PROVE_RCU should detect this sort of thing,
> > > > though.
> > > 
> > > Well, interrupts/NMIs can happen when idle, but the interrupt/NMI
> > > entry code deals with the idle state AFAIK.
> > 
> > Yep, rcu_irq_enter() and rcu_nmi_enter() deal with that.  More worried
> > about this being code invoked from some energy-efficiency driver or
> > another within the idle loop.
> 
> Right, so any tracepoint can end up there; but I thought there was
> already the rule that tracepoints needed RCU enabled.

There is and we have special tracepoint caller for those cases we want a
tracepoint out of RCU scope. These will reactivate rcu in the
tracepoint code.

  trace_<tp_name>_rcuidle(...)

-- Steve
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/