Subject: Re: [PATCH][RFC] preempt_count corruption across H_CEDE call with CONFIG_PREEMPT on pseries

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 23 Jul 2010 08:25:09 +1000

On Thu, 2010-07-22 at 11:24 -0700, Darren Hart wrote:
> 
> 1) How can the preempt_count() get mangled across the H_CEDE hcall?
> 2) Should we call preempt_enable() in cpu_idle() prior to cpu_die() ?

The preempt count is on the thread info at the bottom of the stack.

Can you check the stack pointers ?

Cheers,
Ben.