From: Todd Brandt <todd.e.brandt@linux.intel.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
len.brown@intel.com, todd.e.brandt@intel.com
Subject: Re: [BUG] function_graph trace causes hang when using sleepgraph (4.15.0-rc1 and newer)
Date: Mon, 08 Jan 2018 17:25:15 -0800 [thread overview]
Message-ID: <1515461115.17761.12.camel@linux.intel.com> (raw)
In-Reply-To: <20180108200756.08712bb4@vmware.local.home>
On Mon, 2018-01-08 at 20:07 -0500, Steven Rostedt wrote:
> On Mon, 08 Jan 2018 17:02:29 -0800
> Todd Brandt <todd.e.brandt@linux.intel.com> wrote:
>
> > Stephen, the problem is reversed by removing the following two
> > commits,
> > the one the bisect showed and the very next. So the problem is
> > here:
> >
> > commit 1a149d7d3f45d311da1f63473736c05f30ae8a75
> > Author: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Date: Fri Sep 22 16:59:02 2017 -0400
> >
> > ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler
>
> This one still doesn't make sense, for why it would cause the hang.
>
>
> > commit 12ecef0cb12102d8c034770173d2d1363cb97d52
> > Author: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > Date: Thu Sep 21 16:22:49 2017 -0400
> >
> > tracing: Reverse the order of trace_types_lock and event_mutex
>
> This one does.
>
> Can you run lockdep when you do this and see if lockdep catches
> anything? If it does, it should point directly to where the inversed
> locking happened.
Can you reproduce the issue there? I just want to be sure it's not
something local to our machines here, as long as you have CONFIG_PM
enabled it should work the same hopefully.
I'll give lockdep a try here.
>
> -- Steve
next prev parent reply other threads:[~2018-01-09 1:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 23:55 [BUG] function_graph trace causes hang when using sleepgraph (4.15.0-rc1 and newer) Todd Brandt
2018-01-09 1:02 ` Todd Brandt
2018-01-09 1:07 ` Steven Rostedt
2018-01-09 1:25 ` Todd Brandt [this message]
2018-01-09 3:07 ` Todd Brandt
2018-01-09 16:13 ` Steven Rostedt
2018-01-11 0:21 ` Todd Brandt
2018-01-18 17:21 ` Todd Brandt
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