Re: [PATCH 5/5] ring-buffer: fix printk output

Ingo Molnar
2009-04-29T20:16:20Z

* Valdis.Kletnieks@vt.edu <Valdis.Kletnieks@vt.edu> wrote:

> On Tue, 28 Apr 2009 23:20:00 PDT, Andrew Morton said:
> > printk_once() is racy on smp and preempt btw ;)
>
> Looks like at worst, it's prone to the usual printk racing, plus a
> possible misfire causing it to print twice before shutting up? Or
> is there something I'm missing here?

Yeah, that's the worst-case scenario.

Still worth improving if we can do it without bloating the code or
data.

[ If not, we can just assume the kernel is perfect and ignore all
the printk_once() and WARN_ONCE() / WARN_ON_ONCE() callsites as
obviously dead code ;-) ]

Ingo