Subject: Re: [PATCH -next 0/3] x86 insn decoder test updates (Re: linux-next: Tree for October 29 (x86 posttest))

From: Ingo Molnar <[email-masked]>
Date: Tue, 17 Nov 2009 07:13:52 +0100

* Masami Hiramatsu <[email-masked]> wrote:

> Here are the patches which update x86 instruction decoder build-time 
> test. As Stephen reported on linux-next, sometimes objdump decodes bad 
> instructions as normal. This will cause a false positive result on x86 
> insn decoder test. This patches update the test as below;
>
>  - Show more information with V=1
>  - Show in which symbol the difference places.
>  - Just warning instead of build failure.

yes, -tip testing was showing such build bugs too:

 Error: ffffffff8104aae3:	c5 83 3d 49 80 ee    	lds    0xffffffffee80493d(%rbx),%eax
 Error: objdump says 6 bytes, but insn_get_length() says 3 (attr:0)

it happens with older tools, such as binutils-2.17. Modern binutils 
(2.19) is fine.

We dont want to remove the build error: it helped us fix a number of 
real bugs in the decoder - instead please try to create a make based 
workaround based on binutils, to not run the test with binutils older 
than 2.19 or so.

Thanks,

	Ingo