Re: [Xen-devel] [RFC v3 13/13] kprobes: port blacklist kprobes to linker table

["Luis R. Rodriguez" <mcgrof@xxxxxxxxxx>]

On Tue, Jul 26, 2016 at 12:27:22AM +0900, Masami Hiramatsu wrote:
> On Fri, 22 Jul 2016 14:24:47 -0700
> "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> wrote:
> 
> > kprobe makes use of two sections, the one dealing with the actual
> > kprobes was recently ported using the standard section range API.
> > The blacklist functionality of kprobes is still using a custom
> > section and declaring its custom section using the linker script
> > as follows:
> > 
> > type  Linux-section custom section name  begin                    end
> > table .init.data    _kprobe_blacklist    __start_kprobe_blacklist 
> > __stop_kprobe_blacklist
> > 
> > This ports the _kprobe_blacklist custom section to the standard
> > Linux linker table API allowing us remove all the custom blacklist
> > kprobe section declarations from the linker script.
> > 
> > This has been tested by trying to register a kprobe on a blacklisted
> > symbol (these are declared with NOKPROBE_SYMBOL()), and confirms that
> > this fails to work as expected. This was tested with:
> 
> This is OK for me, and if you would like to make sure, please use ftrace to 
> probe
>  (easier  than making new module) and compare debugfs/blacklist which shows
> all blacklisted functions, so if all the function names are same it
> must be OK :).

Ah I see, sure thanks for the tip! I was actually hoping to write a unit
test that automates this testing, but that can be done and submitted later,
the approach you suggest should make writing a unit easier as well.

> Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Great, thanks,

  Luis

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