Subject: Re: linux-next: add utrace tree

From: Linus Torvalds <[email-masked]>
Date: Fri, 22 Jan 2010 13:59:11 -0800 (PST)

On Fri, 22 Jan 2010, Frank Ch. Eigler wrote:
> 
> Finally, I don't know how to address the logic of "if a feature
> requires utrace, that's a bad argument for utrace" and at the same
> time "you need to show a killer app for utrace".  What could possibly
> satisfy both of those constraints?  Please advise.

The point is, the feature needs to be a killer feature. And I have yet to 
hear _any_ such killer feature, especially from a kernel maintenance 
standpoint.

The "better ptrace than ptrace" is irrelevant. Sure, we all know ptrace 
isn't a wonderful feature. But it's there, and a debugger is going to have 
support for it anyway, so what's the _advantage_ of a "better ptrace 
interface"? There is absolutely _zero_ advantage, there's just "yet 
another interface". We can't get rid of the old one _anyway_.

And the seccomp replacement just sounds horrible. Using some tracing 
interface to implement security models sounds like the worst idea ever.

And like it or not, over the last almost-decade, _not_ having to have to 
work with system tap has been a feature, not a problem, for the kernel 
community.

So what's the killer feature?

			Linus