Re: Linux 3.18 released

[Ingo Molnar <mingo@kernel.org>]

* Vince Weaver <vince@deater.net> wrote:

> On Sun, 7 Dec 2014, Linus Torvalds wrote:
> 
> > I'd love to say that we've figured out the problem that plagues 3.17
> > for a couple of people, but we haven't. At the same time, there's
> > absolutely no point in having everybody else twiddling their thumbs
> > when a couple of people are actively trying to bisect an older issue,
> > so holding up the release just didn't make sense. Especially since
> > that would just have then held things up entirely over the holiday
> > break.
> > 
> > So the merge window for 3.19 is open, and DaveJ will hopefully get his
> > bisection done (or at least narrow things down sufficiently that we
> > have that "Ahaa" moment) over the next week. But in solidarity with
> > Dave (and to make my life easier too ;) let's try to avoid introducing
> > any _new_ nasty issues, ok?
> 
> It's probably unrelated to DaveJ's issue, but my perf_event 
> fuzzer still quickly locks the kernel pretty solid on 3.18.

I'm really tempted to restrict most of the weirder perf ABI 
details (such as event groups, raw events, etc.) to root only 
(with a perf_event_paranoid level to make it available for power 
users and distros so inclined) - most of the past lockups/races 
you have triggered were in such weird, seldom used corners of the 
perf ABI that doesn't get much testing outside Trinity fuzzing.

The bits used by tools/perf and used by the majority of users are 
generally rock solid.

Doing that is not a fix obviously and we'd like to fix all 
pending bugs for real as well, but would at least isolate the 
impact to root-only until it's fixed.

Thanks,

	Ingo