Re: [PATCH v2 1/4] nmi_backtrace: add more trigger_*_cpu_backtrace() methods

From: Peter Zijlstra
Date: Thu Mar 17 2016 - 19:13:59 EST

On Thu, Mar 17, 2016 at 03:55:57PM -0700, Paul E. McKenney wrote:
> That said, RCU used to use NMI-based stack traces, but switched to the
> current scheme due to the NMIs having the unfortunate habit of locking
> things up, which IIRC often meant no stack traces at all. If I recall
> correctly, one of the problems was self-deadlock in printk().
> Have these problems been fixed?

Improved is I think the word.

Although I've butchered my printk() into absolute submission :-)