Re: suspicious RCU usage (perf)

From: Steven Rostedt
Date: Mon Aug 26 2013 - 15:03:13 EST


On Mon, 26 Aug 2013 14:29:07 -0400
Dave Jones <davej@xxxxxxxxxx> wrote:

> On Mon, Aug 26, 2013 at 02:18:14PM -0400, Steven Rostedt wrote:
> > On Mon, 26 Aug 2013 13:50:12 -0400
> > Dave Jones <davej@xxxxxxxxxx> wrote:
> > >
> > > This was triggered as a regular user fwiw.
> > > I had not been running perf, or any other tracing. It was just left
> > > fuzzing over the weekend with no interaction at all.
> >
> > So you are telling me that ftrace was enabled by a regular user? If so,
> > that's a huge issue.
>
> quite.
>
> > So my question to you. If you were not running perf or any other
> > tracing, and this is all just non-root user. How the hell did perf
> > function tracing get started on your box????
>
> What mechanisms are available that would trigger it being enabled ?
>
> Is there some path through sys_perf_open_event that might be
> missing a capability check perhaps ?
>

That's a question for Ingo, Peter or Jiri.

-- Steve
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