Date: Wed, 22 Jul 2015 09:40:04 -0500
From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Minfei Huang <mhuang@redhat.com>
Cc: sjenning@redhat.com, jkosina@suse.cz, vojtech@suse.cz,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
        Minfei Huang <mnfhuang@gmail.com>
Subject: Re: [PATCH] livepatch: Fix the issue to make livepatch
 enable/disable patch correctly
Message-ID: <20150722144004.GC23235@treble.redhat.com>
References: <1436950506-5252-1-git-send-email-mhuang@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <1436950506-5252-1-git-send-email-mhuang@redhat.com>
User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1493
Lines: 36

On Wed, Jul 15, 2015 at 04:55:06PM +0800, Minfei Huang wrote:
> From: Minfei Huang <mnfhuang@gmail.com>
> 
> Livepatch will obey the stacking rule to enable/disable the patch. It
> only allows to enable the patch, when it is the fist disabled patch,
> disable the patch, when it is the last enabled patch.
> 
> In the livepatch code, it uses list to gather the all of the patches.
> And we do not know whether the previous/next patch is patched to the
> same modules or vmlinux in that way.
> 
> According to above rule, livepatch will make incorrect decision to
> enable/disable the patch. Following is an example to show how livepatch
> does.
> 
> - install the livepatch example module which is in samples/livepatch.
> - install the third part kernel module
> - install the livepatch module which is patched to the third part module
> - disable the livepatch example module
> 
> We can find that we can not disable livepatch example module, although
> it is the last enabled patch.
> 
> To fix this issue, we will find the corresponding patch which is patched
> to the same modules or vmlinux, when we enable/disable the patch.

Is it really safe to assume that there are no dependencies between
patches which patch different objects?

-- 
Josh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/