Date: Wed, 1 Mar 2017 22:28:43 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Todd Brandt <todd.e.brandt@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: ftrace_graph_filter not working correctly since v4.10
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On Wed, 01 Mar 2017 18:01:31 -0800
Todd Brandt <todd.e.brandt@linux.intel.com> wrote:

> I've been using early boot trace to gather callgraph data on filtered
> functions but something appears to have broken it in v10.0. The graph
> trace worked fine in v4.10-rc8, so something changed since the release.
> 
> Issue:
> Using the ftrace_graph_filter kernel parameter to filter on a specific
> function produces no data (msleep for instance). The graph trace also
> continues to produce nothing even after reconfiguring it through
> debugfs. It worked fine in v4.10-rc8 but fails in v4.10.
> 

4.10 is fine. It's what has been merged for 4.11 that's broken. I'm
doing a bisect now to see what broke it. Yes, lots of commits touched
that code recently.

I'll have to add this command line as one of my tests I perform.

Thanks!

-- Steve