Re: "stack state/frame" and "jump dest instruction" errors (was Re: Linux 6.16)

[Google]

On Tue, 29 Jul 2025 22:40:00 +0900
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote:

> On Mon, 28 Jul 2025 08:42:44 -0700
> Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> 
> > On Mon, Jul 28, 2025 at 09:41:35AM +0100, Alan J. Wylie wrote:
> > > #regzbot introduced: 6.15.8..6.16
> 
> > I don't have time to look at this for at least the next few days, but I
> > suspect this one:
> > 
> >      1a3:	8f ea 78 10 c3 0a 06 00 00 	bextr  $0x60a,%ebx,%eax
> 
> Thanks for finding!
> Indeed, this is encoded by XOP which is not currently supported
> by x86 decodeer. 
> 
> > 
> > in which case the kernel's x86 decoder (which objtool also uses) needs
> > to be updated.
> 
> OK, let me see how XOP works.

I've sent it to;

https://lore.kernel.org/all/175386161199.564247.597496379413236944.stgit@devnote2/

I confirmed it worked with the XOP encoded "bextr".

Thank you,

-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>