[ktap] Re: [PATCH] FFI support for ktap
- From: Yicheng <qycqycqycqycqyc@xxxxxxxxx>
- To: ktap@xxxxxxxxxxxxx
- Date: Mon, 4 Nov 2013 14:44:44 -0500
IMHO, the FFI feature should have the same priority as 'insmod' operations.
Because what FFI API can do is the same as (or subset of) kernel modules,
it should
be fine if it is managed as kernel modules.
2013/11/4 Qingping Hou <dave2008713@xxxxxxxxx>
> On Mon 04 Nov 2013 08:06:18 AM EST, Jovi Zhangwei wrote:
> >>> I planed to use a command option like "guru mode"(similar with
> Systemtap)
> >>> in ktap, but I also doubt whether the command option really is enough
> to
> >>> make
> >>> ktap safe, user still can crash the kernel easily on ktap installed
> >>> system, like
> >>> the example you posted, just call the schedule in atomic context.
> >>>
>
> ktapc will be able to detect whehter user is using FFI API later because
> we will be parsing C function defitnion and generating ktap vm chunk
> accordingly. So IMHO guru mode is enough to prevent user running FFI
> enabled ktap script in compilation time. That said, they can still feed
> in unsafe chunk directly to ktap VM, which I doubt anyone will do unless
> they want to crash the kernel intentionally ;p
>
> So if we want to have a complete safe ktap runtime, CONFIG_KTAP_FFI and
> sysctl is the way to go. FFI should be easy to disable at runtme since
> all FFI features are accessed by indexing into global C table, we can
> just set that table to nil.
>
>
>
>
--
Sincerely,
Yicheng Qin
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