Re: [PATCH 7/7] DWARF: add the config option

[Vojtech Pavlik]

On Sun, May 07, 2017 at 04:48:36PM -0500, Josh Poimboeuf wrote:

> > Can objtool verify the unwinder at each address in the kernel, or is that an AI-complete problem?
> 
> It can't verify the *unwinder*, but it can verify the data which is fed
> to the unwinder (either DWARF or the structs I proposed above).  For
> each function, it follows every possible code path, and it can keep
> track of the stack pointer while doing so.

In that case, the kernel build process can verify the DWARF data and its
compatibility with the kernel unwinder by running the unwinder against
each kernel code address verifying the output and bail if there is a bug
in the toolchain that affects it.

-- 
Vojtech Pavlik
Director SuSE Labs