From: Masami Hiramatsu on
Srikar Dronamraju wrote:
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index c681fa7..16e2a8c 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -482,6 +482,22 @@ config RING_BUFFER_BENCHMARK
>
> If unsure, say N.
>
> +config UPROBE_EVENT
> + bool "Enable uprobes-based dynamic events"
> + depends on ARCH_SUPPORTS_UPROBES
> + depends on MMU
> + select UPROBES
> + select PROBE_EVENTS
> + select TRACING
> + default n
> + help
> + This allows the user to add tracing events on top of userspace dynamic
> + events (similar to tracepoints) on the fly via the traceevents interface.
> + Those events can be inserted wherever uprobes can probe, and record
> + various registers.
> + This option is required if you plan to use perf-probe subcommand of perf
> + tools on user space applications.
> +

Possible enhancement: Moving this config right after KPROBE_EVENT, because
those two provide similar dynamic events.

Thank you,
--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt(a)hitachi.com
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From: Masami Hiramatsu on
Srikar Dronamraju wrote:
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index c681fa7..16e2a8c 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -482,6 +482,22 @@ config RING_BUFFER_BENCHMARK
>
> If unsure, say N.
>
> +config UPROBE_EVENT
> + bool "Enable uprobes-based dynamic events"
> + depends on ARCH_SUPPORTS_UPROBES
> + depends on MMU
> + select UPROBES
> + select PROBE_EVENTS
> + select TRACING
> + default n
> + help
> + This allows the user to add tracing events on top of userspace dynamic
> + events (similar to tracepoints) on the fly via the traceevents interface.
> + Those events can be inserted wherever uprobes can probe, and record
> + various registers.
> + This option is required if you plan to use perf-probe subcommand of perf
> + tools on user space applications.
> +

Possible enhancement: Moving this config right after KPROBE_EVENT, because
those two provide similar dynamic events.

Thank you,
--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt(a)hitachi.com

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From: Masami Hiramatsu on
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(a)hitachi.com
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