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SubjectRe: suspicious RCU usage (perf)
On Mon, Aug 26, 2013 at 01:43:15PM -0600, David Ahern wrote:
> On 8/26/13 12:29 PM, Dave Jones 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@redhat.com> 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 ?
>
> Do you have /sys/kernel/debug with access permissions?

Ah, yeah, that'll be it. Good catch.

Sorry for the false alarm Steve ;)

Dave



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