Date: Fri, 22 Dec 2017 14:12:59 +0100 (CET)
From: Miroslav Benes <mbenes@suse.cz>
To: Petr Mladek <pmladek@suse.com>
cc: jpoimboe@redhat.com, jeyu@kernel.org, jikos@kernel.org,
        linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
        jbaron@akamai.com
Subject: Re: [PATCH 2/2] livepatch: Allow loading modules on architectures
 without HAVE_RELIABLE_STACKTRACE
In-Reply-To: <20171221151428.rt4dlizxb5nqhb3h@pathway.suse.cz>
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References: <20171208172523.12150-1-mbenes@suse.cz> <20171208172523.12150-3-mbenes@suse.cz> <20171221151428.rt4dlizxb5nqhb3h@pathway.suse.cz>
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On Thu, 21 Dec 2017, Petr Mladek wrote:

> On Fri 2017-12-08 18:25:23, Miroslav Benes wrote:
> > Now that immediate feature was removed, it is not possible to load
> > livepatch modules on architectures without HAVE_RELIABLE_STACKTRACE. Fix
> > it by removing guilty check in klp_register_patch().
> > 
> > The architectures without HAVE_RELIABLE_STACKTRACE will now rely only on
> > kernelspace/userspace boundary switching, the (fake) signal and force
> > feature.
> 
> I do not thing that this is a good idea. It encourages people to use
> the force feature. They might get used to it.
> 
> If people are going to provide livepatches, they should be capable
> enough to provide a kernel where it is allowed. IMHO, the upstream
> kernel should not support bad/dirty practices out of box.

You're probably right.

It is true that with immediate gone the only reasonable thing for all 
supported architectures is to provide HAVE_RELIABLE_STACKTRACE.

Miroslav