From: "chengjian (D)" <cj.chengjian@huawei.com>
To: <linux-kernel@vger.kernel.org>, <live-patching@vger.kernel.org>
Cc: <chenwandun@huawei.com>, <xiexiuqi@huawei.com>,
<bobo.shaobowang@huawei.com>, <huawei.libin@huawei.com>,
<jeyu@kernel.org>, <jikos@kernel.org>
Subject: Re: [PATCH] module: make module symbols visible after init
Date: Thu, 4 Jun 2020 20:55:46 +0800 [thread overview]
Message-ID: <14e1413f-92a2-f228-e149-82d4fdbc0c0d@huawei.com> (raw)
In-Reply-To: <20200603141200.17745-1-cj.chengjian@huawei.com>
Hi, Petr, Jessica and Miroslav
Thank you for your reply
On 2020/6/4 16:57, Petr Mladek wrote:
> On Wed 2020-06-03 14:12:00, Cheng Jian wrote:
>
> It is really handful that module symbols can be found already when
> the module is MODULE_STATE_COMING state. It is used by livepatching,
> ftrace, and maybe some other subsystems.
Yes, you are right, I missed this before.
There are many scenes that lookup the symbols of module when the module is
MODULE_STATE_COMING state.
in livepatch:
klp_module_coming
-=> klp_write_object_relocations
-=> klp_resolve_symbols
-=> module_kallsyms_on_each_symbol
My patch is incorrect.
> The problem is that nobody is allowed to use (call) module symbols
> before mod->init() is called and the module is moved to
> MODULE_STATE_LIVE.
>
> By other words. Any code that calls module symbols before the module
> is fully initialized is buggy. The caller should get fixed,
> not the kallsyms side.
>
> Have you seen such a problem in the real life, please?
>
> Best Regards,
> Petr
>
> .
Thank you very much.
-- Cheng Jian.
prev parent reply other threads:[~2020-06-04 12:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 14:12 [PATCH] module: make module symbols visible after init Cheng Jian
2020-06-03 17:00 ` Miroslav Benes
2020-06-04 9:49 ` Jessica Yu
2020-06-04 8:57 ` Petr Mladek
2020-06-04 12:55 ` chengjian (D) [this message]
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