Re: [PATCH 1/5] ftrace: use module notifier for function tracer

From: Masami Hiramatsu
Date: Wed Apr 22 2009 - 18:58:39 EST


Tim Abbott wrote:
> On Wed, 22 Apr 2009, Ingo Molnar wrote:
>
>> I suspect ksplice could make use of text_mutex?
>
> Yes, this is what I was imagining. Thanks for pointing this out! I plan
> to make Ksplice use this for the next version of the Ksplice patch series.

Could you also add "use text_poke() on x86" to your plan? :-)

> However, since Ksplice can be built as a module, we'll want to
> EXPORT_SYMBOL_GPL(text_mutex). The comment above text_mutex's definition
> suggests some people would prefer not to have modules patching the kernel
> text, and so this point might be contentious. I've found support for
> building Ksplice as a module to be a useful feature in case one needs to
> use multiple different versions of Ksplice on the same system (e.g.
> because the version built in to the kernel doesn't support a particular
> patch).

Hmm, I can't agree that we allow module to modify kernel text...
Is that possible to separate kernel-text swapping routine from Ksplice
module? In that case, we don't need to export text_mutex.

Thank you,

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@xxxxxxxxxx

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