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SubjectRe: suspicious RCU usage (perf)
On Tue, Aug 27, 2013 at 07:58:12AM -0600, David Ahern wrote:
> On 8/27/13 7:10 AM, Steven Rostedt wrote:
> > On Mon, 26 Aug 2013 15:49:24 -0400
> > Dave Jones <davej@redhat.com> wrote:
> >
> >
> >> > Do you have /sys/kernel/debug with access permissions?
> >>
> >> Ah, yeah, that'll be it. Good catch.
> >>
> >> Sorry for the false alarm Steve ;)
> >
> > Yeah, but it still does not explain how perf got started. Perf requires
> > a sys_perf_event_open() call to run.
>
> Per Peter's response another option is the paranoia level:
>
> # perf event paranoia level:
> # -1 - not paranoid at all
> # 0 - disallow raw tracepoint access for unpriv
> # 1 - disallow cpu events for unpriv
> # 2 - disallow kernel profiling for unpriv
> kernel.perf_event_paranoid = -1

This I have set to 1 on that box. (The default)

Dave



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