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Re: [PATCHv10 2.6.35-rc6-tip 9/14] trace: uprobes trace_event interface
- From: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- To: Christoph Hellwig <hch at infradead dot org>
- Cc: Ingo Molnar <mingo at elte dot hu>, Frederic Weisbecker <fweisbec at gmail dot com>, Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>, Peter Zijlstra <peterz at infradead dot org>, Steven Rostedt <rostedt at goodmis dot org>, Randy Dunlap <rdunlap at xenotime dot net>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Oleg Nesterov <oleg at redhat dot com>, Mark Wielaard <mjw at redhat dot com>, Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>, Andrew Morton <akpm at linux-foundation dot org>, Naren A Devaiah <naren dot devaiah at in dot ibm dot com>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, "Frank Ch. Eigler" <fche at redhat dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, LKML <linux-kernel at vger dot kernel dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>, 2nddept-manager at sdl dot hitachi dot co dot jp, SystemTAP <systemtap at sources dot redhat dot com>
- Date: Mon, 02 Aug 2010 18:29:27 +0900
- Subject: Re: [PATCHv10 2.6.35-rc6-tip 9/14] trace: uprobes trace_event interface
- References: <20100727110855.24690.26901.sendpatchset@localhost6.localdomain6> <20100727111045.24690.31897.sendpatchset@localhost6.localdomain6> <4C510BCE.4010704@hitachi.com> <20100802022055.GB5581@nowhere> <4C563F44.9080300@hitachi.com> <20100802074619.GA5292@nowhere> <20100802075637.GB24085@elte.hu> <20100802080032.GA12078@infradead.org>
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@hitachi.com