From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>,
Dave Jones <davej@redhat.com>, Tejun Heo <tj@kernel.org>,
tglx@linutronix.de, LKML <linux-kernel@vger.kernel.org>,
trinity@vger.kernel.org
Subject: Re: timer: lockup in run_timer_softirq()
Date: Thu, 11 Jul 2013 12:59:32 -0400 [thread overview]
Message-ID: <1373561972.17876.51.camel@gandalf.local.home> (raw)
In-Reply-To: <1373561726.17876.48.camel@gandalf.local.home>
On Thu, 2013-07-11 at 12:55 -0400, Steven Rostedt wrote:
> >
> > Other than that, a function tracer environment that is safer to use might be
> > useful for other people as well.
>
> Not sure how to make the environment safe, as the main purpose of the
> function trace is to debug those hard to debug locations, like NMIs,
> RCU, dynamic ticks, etc. To ensure a "safe" environment, it would
> cripple the tracer.
>
> Hmm, what would you state as a safe environment? How can we detect if
> the environment is safe to trace or not?
Maybe I misunderstood you. You mean to have this environment be
something for not just perf, and have the macro be:
NONSAFE_TRACE(__local_bh_enable);
?
Then, any ftrace user could set a flag in the registering of its ops to
'safe_only_functions'. And it will ignore all of these locations.
There's really not many of them, so it may not be too hard to weed out.
-- Steve
next prev parent reply other threads:[~2013-07-11 16:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-09 22:35 timer: lockup in run_timer_softirq() Sasha Levin
2013-07-09 22:47 ` Dave Jones
2013-07-09 22:49 ` Sasha Levin
2013-07-09 23:03 ` Dave Jones
2013-07-09 23:09 ` Sasha Levin
2013-07-10 9:52 ` Peter Zijlstra
2013-07-10 12:27 ` Steven Rostedt
2013-07-10 12:42 ` Peter Zijlstra
2013-07-10 12:58 ` Steven Rostedt
2013-07-11 16:42 ` Peter Zijlstra
2013-07-11 16:55 ` Steven Rostedt
2013-07-11 16:59 ` Steven Rostedt [this message]
2013-07-11 17:11 ` Peter Zijlstra
2014-04-03 20:43 ` Sasha Levin
2013-07-10 9:54 ` Peter Zijlstra
2013-07-10 14:47 ` Sasha Levin
2013-07-11 10:02 ` Peter Zijlstra
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