Re: [PATCH v12 0/3] tracing: Centralize preemptirq tracepoints and unify their usage

From: Masami Hiramatsu <mhiramat@kernel.org>
To: Joel Fernandes <joelaf@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Cc: Android Kernel" <kernel-team@android.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Byungchul Park <byungchul.park@lge.com>,
	Ingo Molnar <mingo@redhat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Glexiner <tglx@linutronix.de>,
	Tom Zanussi <tom.zanussi@linux.intel.com>
Subject: Re: [PATCH v12 0/3] tracing: Centralize preemptirq tracepoints and unify their usage
Date: Fri, 3 Aug 2018 16:23:40 +0900	[thread overview]
Message-ID: <20180803162340.32b4b3fde55a4f5a5c28b425@kernel.org> (raw)
In-Reply-To: <CAJWu+opoT6Ky-pwAwBbjDkyt0Y_UF1QUnDshu-_vLTU5K87_HQ@mail.gmail.com>

Hi Joel,

Thank you for trying to fix that.

On Thu, 2 Aug 2018 19:57:09 -0700
Joel Fernandes <joelaf@google.com> wrote:

> Hi Masami,
> 
> On Thu, Aug 2, 2018 at 7:55 AM, Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > Hi Joel,
> >
> > I found this caused several issues when testing ftrace.
> >
> > #1) ftrace boottest (FTRACE_STARTUP_TEST) fails
> 
> This sadly appears to be a real issue. The startup test for
> "preemptirqsoff" tracer fails, however it passes for only preemptoff
> or only irqsoff. I tested only the last 2 tracers, not the first one,
> that's why I didn't catch it. I need to debug this more.
> 
> > #2) mmiotrace reports "IRQs not enabled as expected" error
> > #3) lock subsystem event boottest causes "IRQs not disabled as expected" error (sometimes)
> 
> Could you try the below patch and let me know if you still see the
> issue? In the v11 I removed the lockdep_recursing() check since it
> seemed unnecessary. But I'd like to rule out that there's still some
> issue lurking there. Thanks and I appreciate your help, diff is
> attached to this email.

I tried the attached patch. But unfortunately I still see #1 and #2.
(#3 does not always occurred, I'll continue to test)

> > #4) ftracetest test.d/event/toplevel-enable.tc causes "suspicious RCU usage" warning
> 
> I sent a patch fixing this with you on CC. I tested that it fixes the
> issue you're reporting.

OK, I'll check it.

Thanks!

-- 
Masami Hiramatsu <mhiramat@kernel.org>