Re: [PATCH] x86/dumpstack/64: Don't evaluate exception stacks before setup

[Matthew Wilcox]

On Wed, Oct 23, 2019 at 08:05:49PM +0200, Thomas Gleixner wrote:
> Prevent this by checking the validity of the cea_exception_stack base
> address and bailing out if it is zero.

Could also initialise cea_exception_stack to -1?  That would lead to it
being caught by ...

>  	end = begin + sizeof(struct cea_exception_stacks);
>  	/* Bail if @stack is outside the exception stack area. */
>  	if (stk < begin || stk >= end)

this existing check.