From: Dave Jones <davej@redhat.com>
To: David Ahern <dsahern@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
paulmck@linux.vnet.ibm.com,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: suspicious RCU usage (perf)
Date: Tue, 27 Aug 2013 10:13:30 -0400 [thread overview]
Message-ID: <20130827141330.GA21890@redhat.com> (raw)
In-Reply-To: <521CB074.3040900@gmail.com>
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
prev parent reply other threads:[~2013-08-27 14:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-26 14:58 suspicious RCU usage (perf) Dave Jones
2013-08-26 16:29 ` Paul E. McKenney
2013-08-26 17:30 ` Steven Rostedt
2013-08-26 17:50 ` Dave Jones
2013-08-26 18:18 ` Steven Rostedt
2013-08-26 18:29 ` Dave Jones
2013-08-26 19:03 ` Steven Rostedt
2013-08-27 12:16 ` Peter Zijlstra
2013-08-30 15:49 ` Frederic Weisbecker
2013-08-30 15:52 ` Frederic Weisbecker
2013-08-30 15:59 ` Peter Zijlstra
2013-08-30 16:06 ` Frederic Weisbecker
2013-08-26 19:43 ` David Ahern
2013-08-26 19:49 ` Dave Jones
2013-08-27 13:10 ` Steven Rostedt
2013-08-27 13:58 ` David Ahern
2013-08-27 14:13 ` Dave Jones [this message]
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