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Subject: Re: linux-5.10.11 build failure
To:     Thomas Backlund <tmb@tmb.nu>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     LKML <linux-kernel@vger.kernel.org>, stable@vger.kernel.org,
        torvic9@mailbox.org
References: <8b3e9d93-1381-b415-9ece-a10fb098b896@tmb.nu>
From:   Chris Clayton <chris2553@googlemail.com>
Message-ID: <9617db49-cf67-3b48-1b31-3bcd34cf3e1a@googlemail.com>
Date:   Thu, 28 Jan 2021 13:38:25 +0000
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Thanks, Thomas.

On 28/01/2021 11:24, Thomas Backlund wrote:
> Den 28.1.2021 kl. 12:05, skrev Chris Clayton:
>>
>> On 28/01/2021 09:34, Greg Kroah-Hartman wrote:
>>> On Thu, Jan 28, 2021 at 09:17:10AM +0000, Chris Clayton wrote:
>>>> Hi,
>>>>
>>>> Building 5.10.11 fails on my (x86-64) laptop thusly:
>>>>
>>>> ..
>>>>
>>>>   AS      arch/x86/entry/thunk_64.o
>>>>    CC      arch/x86/entry/vsyscall/vsyscall_64.o
>>>>    AS      arch/x86/realmode/rm/header.o
>>>>    CC      arch/x86/mm/pat/set_memory.o
>>>>    CC      arch/x86/events/amd/core.o
>>>>    CC      arch/x86/kernel/fpu/init.o
>>>>    CC      arch/x86/entry/vdso/vma.o
>>>>    CC      kernel/sched/core.o
>>>> arch/x86/entry/thunk_64.o: warning: objtool: missing symbol for insn at offset 0x3e
>>>>
>>>>    AS      arch/x86/realmode/rm/trampoline_64.o
>>>> make[2]: *** [scripts/Makefile.build:360: arch/x86/entry/thunk_64.o] Error 255
>>>> make[2]: *** Deleting file 'arch/x86/entry/thunk_64.o'
>>>> make[2]: *** Waiting for unfinished jobs....
>>>>
>>>> ..
>>>>
>>>> Compiler is latest snapshot of gcc-10.
>>>>
>>>> Happy to test the fix but please cc me as I'm not subscribed
>>>
>>> Can you do 'git bisect' to track down the offending commit?
>>>
>>
>> Sure, but I'll hold that request for a while. I updated to binutils-2.36 on Monday and I'm pretty sure that is a feature
>> of this build fail. I've reverted binutils to 2.35.1, and the build succeeds. Updated to 2.36 again and, surprise,
>> surprise, the kernel build fails again.
>>
>> I've had a glance at the binutils ML and there are all sorts of issues being reported, but it's beyond my knowledge to
>> assess if this build error is related to any of them.
>>
>> I'll stick with binutils-2.35.1 for the time being.
>>
>>> And what exact gcc version are you using?
>>>
>>
>>   It's built from the 10-20210123 snapshot tarball.
>>
>> I can report this to the binutils folks, but might it be better if the objtool maintainer looks at it first? The
>> binutils change might just have opened the gate to a bug in objtool.
>>
>>> thanks,
>>>
>>> greg k-h
>>>
>>
> 
> 
> AFAIK you need this in stable trees:
> 
>  From 1d489151e9f9d1647110277ff77282fe4d96d09b Mon Sep 17 00:00:00 2001
> From: Josh Poimboeuf <jpoimboe@redhat.com>
> Date: Thu, 14 Jan 2021 16:14:01 -0600
> Subject: [PATCH] objtool: Don't fail on missing symbol table
> 
> 

That may be the caae, but it doesn't fix the build failure I've reported in this thread. However, as suggested by Tor,
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/patch/?id=5e6dca82bcaa49348f9e5fcb48df4881f6d6c4ae does fix it.

That hasn't made Linus' tree yet and I don't see a pull request, but it is in linux-next so I guess it could make it in
-rc6.

Chris
> --
> Thomas
>