Bad mode in undefined instruction handler detected

[Russell King - ARM Linux]

On Tue, Mar 29, 2016 at 02:22:29PM -0400, Patrick Doyle wrote:
> Hmmm... inexplicably, compiling with frame pointers enabled doesn't
> seem to be an option for me :-(

Right, because the Kconfig system is setup to use a frame pointer
when the configuration options allow it, because not having it hurts
the ability to get sensible debugging from kernel crashes.

> with no option to set CONFIG_FRAME_POINTER in between.  Could that be
> because FRAME_POINTER looks like:
> 
> config FRAME_POINTER
>     bool
>     depends on !THUMB2_KERNEL
>     default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
>     help
>       If you say N here, the resulting kernel will be slightly smaller and
>       faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled,
>       when a problem occurs with the kernel, the information that is
>       reported is severely limited.
> 
> -- that is, not prompt for the "bool" option?  Is this an either/or
> choice for ARM_UNWIND vs FRAME_POINTER?

THUMB2_KERNEL is an option, which I believe you already have disabled.
So, the offending option is probably ARM_UNWIND.  You are provided with
the ARM_UNWIND option, and you need to say no to that.  Don't try to
build a kenrel with frame pointers and unwinding together - it'll
probably fail, or if you succeed in building it, it probably won't
work correctly since that's a combination we don't support.

-- 
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