From: David Ahern <dsahern@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Dave Jones <davej@redhat.com>,
paulmck@linux.vnet.ibm.com,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: suspicious RCU usage (perf)
Date: Tue, 27 Aug 2013 07:58:12 -0600 [thread overview]
Message-ID: <521CB074.3040900@gmail.com> (raw)
In-Reply-To: <20130827091011.18ed8b59@gandalf.local.home>
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
I keep my dev box at -1 and set /sys/kernel/debug to 755 to run perf as
non-root.
David
next prev parent reply other threads:[~2013-08-27 13:58 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 [this message]
2013-08-27 14:13 ` Dave Jones
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