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

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Message-ID: <20200120153743.z6ws3jbgnsmsjvvx@treble>
Date:   Mon, 20 Jan 2020 09:37:43 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Randy Dunlap <rdunlap@...radead.org>
Cc:     Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux Next Mailing List <linux-next@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: linux-next: Tree for Nov 15 (objtool)

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