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

From: Ingo Molnar
Date: Sun Mar 22 2009 - 08:38:29 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> 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
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