linux-kernel - Re: [PATCH v5] ftrace/module: remove ftrace module notifier

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Date:	Wed, 17 Feb 2016 15:36:33 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Jiri Kosina <jikos@...nel.org>
Cc:	Jessica Yu <jeyu@...hat.com>, Josh Poimboeuf <jpoimboe@...hat.com>,
	Seth Jennings <sjenning@...hat.com>,
	Vojtech Pavlik <vojtech@...e.com>,
	Miroslav Benes <mbenes@...e.cz>,
	Petr Mladek <pmladek@...e.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Ingo Molnar <mingo@...hat.com>, live-patching@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5] ftrace/module: remove ftrace module notifier

On Wed, 17 Feb 2016 21:35:29 +0100 (CET)
Jiri Kosina <jikos@...nel.org> wrote:

> On Tue, 16 Feb 2016, Jessica Yu wrote:
> 
> > Remove the ftrace module notifier in favor of directly calling
> > ftrace_module_enable() and ftrace_release_mod() in the module loader.
> > Hard-coding the function calls directly in the module loader removes
> > dependence on the module notifier call chain and provides better
> > visibility and control over what gets called when, which is important
> > to kernel utilities such as livepatch.
> > 
> > This fixes a notifier ordering issue in which the ftrace module notifier
> > (and hence ftrace_module_enable()) for coming modules was being called
> > after klp_module_notify(), which caused livepatch modules to initialize
> > incorrectly. This patch removes dependence on the module notifier call
> > chain in favor of hard coding the corresponding function calls in the
> > module loader. This ensures that ftrace and livepatch code get called in
> > the correct order on patch module load and unload.
> > 
> > Fixes: 5156dca34a3e ("ftrace: Fix the race between ftrace and insmod")
> > Signed-off-by: Jessica Yu <jeyu@...hat.com>
> > Reviewed-by: Steven Rostedt <rostedt@...dmis.org>  
> 
> Steven, I am going to assume that your Reviewed-by: still holds for the 
> patch even though it has been removed from the 4-patch series; if you 
> don't agree, please speak up. Otherwise, I am going to apply it and push 
> it to Linus for -rc5 still (as it fixes our regression).
> 

This week has been very busy. Did the patch change at all?

-- Steve