Re: [tip:x86/irq] x86: Always use irq stacks

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2010-07-14 at 17:47 +0200, Christoph Hellwig wrote:
> On Wed, Jul 14, 2010 at 05:27:01PM +0200, Thomas Gleixner wrote:
> > On Wed, 14 Jul 2010, Christoph Hellwig wrote:
> > 
> > > Turns out this wasn't a regression introduced by a commit, but it
> > > happens when CONFIG_FUNCTION_GRAPH_TRACER is enabled.  From a quick
> > > look I have no idea why these would interact badly, especially as
> > > CONFIG_FUNCTION_GRAPH_TRACER works fine with irq stacks if the
> > > CONFIG_4KSTACKS options is set.
> > 
> > So you're saying, that the problem appears when
> > CONFIG_FUNCTION_GRAPH_TRACER is enabled w/o being used and that it
> > exists prior to your patches with irq stacks and 8k stack size, but
> > works with 4k stacks. That's definitely more than odd.
> 
> No, the problem does not show up with 8k stack size without irqstacks,
> and does not show up with 4k stacks with irq stacks, but does show up
> with 8k stacks with irqstacks as long as CONFIG_FUNCTION_GRAPH_TRACER is
> enabled. Just disabling it in Ingo's example config makes it work,
> and enabling it in my usual test configs makes the boot fail with
> similar messages to the one Ingo sees.

I'm currently at OLS, but I can take a look at this in more detail when
I get back on Monday.

-- Steve