[PATCH 3/3] utrace-based ftrace "process" engine, v2

[Ingo Molnar]

* Linus Torvalds <torvalds at linux-foundation.org> wrote:

> On Sat, 21 Mar 2009, Frank Ch. Eigler wrote:
> > 
> > > If testing utrace against its main application requires installation
> > > of a complete enterprise distro from a distro [...]
> > 
> > This has *never* been a requirement.
> 
> You guys are getting off a tangent.
> 
> Let's go back to the post that started this all.
> 
> > The thing is, utrace crashes in Fedora have dominated kerneloops.org 
> > for many months, so i'm not sure what to make of the idea of posting 
> > a 4000+ lines of core kernel code patchset on the last day of the 
> > development cycle, a posting that has carefully avoided the Cc:-ing 
> > of affected maintainers ;-)
> 
> .. and dammit, I agree 100%. If utrace really shows up in _any_ 
> way on kerneloops.org, then I think THE ENTIRE DISCUSSION in this 
> thread is moot.
> 
> I'm not going to take known-bad crap. It's that simple. Don't 
> bother posting it, don't bother discussing it, don't bother making 
> excuses for it.

The kerneloops stats on utrace crashes are way down currently,
after that peak last fall. So i didnt want to suggest that it's 
known-broken now - i only wanted to point out that it's a 
known-risky area and that the submission of it should involve
the affected maintainers/developers.

Regarding current stability, Roland, Frank, is the utrace patch in 
latest (today's) Fedora rawhide:

 -rw-r--r-- 1 root root 176555 2009-01-08 05:42 linux-2.6-utrace.patch

a bug fixed equivalent of the utrace bits that crashed in the 
2.6.26.3 kernel? In that case it is certainly known-good.

Or is it a slimmed-down version?

The ptrace bits and signoffs from Oleg and Alexey would certainly 
help (me) in trusting it. (I've Cc:-ed Oleg and Alexey)

The ftrace bits could certainly be staged to go in via the tracing 
tree (in .31 or so) after the utrace-core+ptrace bits went upstream.

	Ingo