linux-kernel - Re: [PATCH 0/3] livepatch: add shadow variable API

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Message-ID: <alpine.LSU.2.20.1706012229410.26873@cbobk.fhfr.pm>
Date:   Thu, 1 Jun 2017 22:32:06 +0200 (CEST)
From:   Jiri Kosina <jikos@...nel.org>
To:     Joe Lawrence <joe.lawrence@...hat.com>
cc:     live-patching@...r.kernel.org, linux-kernel@...r.kernel.org,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Jessica Yu <jeyu@...hat.com>, Miroslav Benes <mbenes@...e.cz>,
        Petr Mladek <pmladek@...e.com>
Subject: Re: [PATCH 0/3] livepatch: add shadow variable API

On Thu, 1 Jun 2017, Joe Lawrence wrote:

>  * the intention is that only livepatched code will be calling
> klp_shadow_*, so it can assume that the current task is patched

Ah, okay, that fully answers my question, thanks. That makes it impossible 
though to apply the same technique to a single variable twice, without 
further tweaks (either versioning of the variables, or actually stacking 
the shadowing itself).

Honestly though, I don't think that's going to be a big issue in practice.

> Maybe I misunderstood the question... if so, I can update the 
> documentation file to better describe what's going on.

I think you didn't misunderstand it. But it might be beneficial to have a 
few additional explanatory words in the documentation nevertheless :)

Thanks,

-- 
Jiri Kosina
SUSE Labs