Subject: Re: [PATCH 3/5] v2 seccomp_filters: Enable ftrace-based system call filtering

From: Ingo Molnar <[email-masked]>
Date: Tue, 24 May 2011 21:54:35 +0200

* Peter Zijlstra <[email-masked]> wrote:

> On Tue, 2011-05-24 at 10:59 -0500, Will Drewry wrote:
> >  include/linux/ftrace_event.h  |    4 +-
> >  include/linux/perf_event.h    |   10 +++++---
> >  kernel/perf_event.c           |   49 +++++++++++++++++++++++++++++++++++++---
> >  kernel/seccomp.c              |    8 ++++++
> >  kernel/trace/trace_syscalls.c |   27 +++++++++++++++++-----
> >  5 files changed, 82 insertions(+), 16 deletions(-) 
> 
> I strongly oppose to the perf core being mixed with any sekurity voodoo
> (or any other active role for that matter).

I'd object to invisible side-effects as well, and vehemently so. But note how 
intelligently it's used here: it's explicit in the code, it's used explicitly 
in kernel/seccomp.c and the event generation place in 
kernel/trace/trace_syscalls.c.

So this is a really flexible solution IMO and does not extend events with some 
invisible 'active' role. It extends the *call site* with an open-coded active 
role - which active role btw. already pre-existed.

Thanks,

	Ingo