Re: [debug patch] printk: Add a printk killswitch to robustify NMIwatchdog messages

From: Ingo Molnar
Date: Mon Jun 06 2011 - 11:08:30 EST



* Ingo Molnar <mingo@xxxxxxx> wrote:

> The real fix might be to remove the lockdep_off()/on() call from
> printk(), that looks actively evil ... we had to hack through
> several layers of side-effects before we found the real bug - so
> it's not like the off()/on() made things more robust!

The other obvious fix would be to *remove* the blasted wakeup from
printk(). It's a serious debugging robustness violation and it's not
like the wakeup is super important latency-wise.

We *already* have a timer tick driven klogd wakeup poll routine. So i
doubt we'd have many problems from not doing wakeups from printk().
Opinions?

Thanks,

Ingo
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