Re: linux-next: Tree for Nov 15 (objtool)

From: Josh Poimboeuf
Date: Mon Jan 20 2020 - 10:37:53 EST


On Fri, Nov 15, 2019 at 10:38:30AM -0600, Josh Poimboeuf wrote:
> On Fri, Nov 15, 2019 at 08:02:30AM -0800, Randy Dunlap wrote:
> > On 11/15/19 12:05 AM, Stephen Rothwell wrote:
> > > Hi all,
> > >
> > > Changes since 20191114:
> > >
> >
> > on x86_64:
> >
> > already reported and Josh supplied a fix (yet unmerged),
> > but this is still around:
> >
> > kernel/exit.o: warning: objtool: __x64_sys_exit_group()+0x14: unreachable instruction
>
> My apologies, I have a growing backlog of objtool fixes which I hope to
> post next week.
>
> >
> > new AFAIK:
> >
> > drivers/gpu/drm/bridge/cdns-dsi.o: warning: objtool: cdns_dsi_bridge_enable()+0x3e0: unreachable instruction
> >
> > obj file for latter one is attached.
>
> This seems fishy. cdns_dsi_init_link() never returns, it always dies a
> with UD2. I bet GCC decided that it always does a divide-by-zero, and
> so it forces a crash as a result. Will try to dig deeper next week...

Hi Randy,

(Digging up old objtool threads...)

This is another one that it would be nice to recreate, so I can open a
GCC bug if needed. If you can still recreate it, can you provide the
config file and GCC version?

--
Josh