Re: Question about qspinlock nest

From: Peter Zijlstra
Date: Thu Jan 10 2019 - 15:03:11 EST


On Thu, Jan 10, 2019 at 04:02:53PM +0800, Zhenzhong Duan wrote:
> Hi Maintainer,
>
>
> There is a question confused me for days. Appreciate an answer.
>
> In below code, the comment says we never have more than 4 nested contexts.
>
> What happen if debug and mce exceptions nest with the four, or we ensure it
> never happen?

MCE and NMI really should not use spinlocks at all since they cannot be
masked.