linux-kernel - Re: [PATCH v6 1/8] x86: allow to handle errors in text

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Date:	Tue, 14 Jan 2014 18:20:29 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Petr Mladek <pmladek@...e.cz>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Jiri Kosina <jkosina@...e.cz>, linux-kernel@...r.kernel.org,
	x86@...nel.org
Subject: Re: [PATCH v6 1/8] x86: allow to handle errors in text_poke
 function family


FYI, for future patches, start the subject with a capital letter. ie:
 x86: Allow to handle errors in text_poke function family

On Tue, 10 Dec 2013 16:42:13 +0100
Petr Mladek <pmladek@...e.cz> wrote:

> The text_poke functions called BUG() in case of error. This was too strict.
> There are situations when the system is still usable even when the patching
> has failed, for example when enabling the dynamic ftrace.
> 
> This commit modifies text_poke and text_poke_bp functions to return an error
> code instead of calling BUG(). They used to return the patched address. But
> the address was just copied from the first parameter. It was no extra
> information and it has not been used anywhere yet.
> 
> There are some situations where it is hard to recover from an error. Masami
> Hiramatsu <masami.hiramatsu.pt@...achi.com> suggested to create
> text_poke*_or_die() variants for this purpose.

I don't like the "_or_die()". Although I don't care much about it, I'm
thinking the x86 maintainers might not like it either.

What about just doing the test in the places that would call "or_die"?

	ret = text_poke*();
	BUG_ON(ret);

?

-- Steve

> 
> Last but not least, we modify return value of the text_poke_early() function.
> It is not capable of returning an error code. Let's return void to make
> it clear.
> 
> Finally, we also need to modify the few locations where text_poke functions
> were used and the error code has to be handled now.
> 
> Signed-off-by: Petr Mladek <pmladek@...e.cz>
> ---

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