Re: [PATCHv10 2.6.35-rc6-tip 9/14] trace: uprobes trace_event interface

From: Masami Hiramatsu
Date: Mon Aug 02 2010 - 05:29:42 EST


Christoph Hellwig wrote:
> On Mon, Aug 02, 2010 at 09:56:37AM +0200, Ingo Molnar wrote:
>>>> Hmm, I disagree with it, because both Kprobes and Uprobes provides
>>>> APIs for modules too.
>>> I'm not sure there is a point in maintaining a leightweight version for out
>>> of tree code. These modules could just select kprobes/uprobes events as
>>> well.
>>>
>>> As you prefer, that was just a suggestion to make it more simple.
>> The upstream policy always was that out of tree code does not exist as far as
>> the kernel is concerned. So it is wrong to make the kernel crappier while
>> helping out of tree code.
>
> Indeed. In addition to that the current version of uprobes does not
> actually have any exported symbols.

Ah, indeed. :-(

And then, it conflicts with the description about uprobes in
Documentation/uprobes.txt:

> +Uprobes-based instrumentation can be packaged as a kernel
> +module. In the simplest case, the module's init function installs
> +("registers") one or more probes, and the exit function unregisters
> +them.

So, that could be a bug.

Anyway, at least kprobes has some sample modules under samples/kprobes/.
Aren't they in-tree consumers of kprobes?

Thank you,

--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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