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Date:   Sun, 25 Sep 2022 20:43:33 +0200
From:   Willy Tarreau <w@1wt.eu>
To:     Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc:     ast@kernel.org, yhs@fb.com, sean.wang@mediatek.com,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: Unable bisect issue because kernel not building from old commits
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On Sun, Sep 25, 2022 at 09:13:13PM +0500, Mikhail Gavrilov wrote:
> On Sun, Sep 25, 2022 at 8:21 PM Willy Tarreau <w@1wt.eu> wrote:
> > Just add:
> >
> >    CROSS_COMPILE=/path/to/toolchain/bin/prefix-
> >
> > to your make command line and it will be fine.
> >
> > The makefile will append {gcc,ld,...} to this CROSS_COMPILE prefix to
> > construct the full pathname to the binaries.
> 
> It works!
> But I hit another build issue.
> 
> $ make clean &&
> CROSS_COMPILE=~/Downloads/x86_64-gcc-7.5.0-nolibc-x86_64-linux/gcc-7.5.0-nolibc/x86_64-linux/bin/x86_64-linux-
> make -j32 bzImage
> ***
>   GEN     modules.builtin
>   LD      .tmp_vmlinux.btf
>   BTF     .btf.vmlinux.bin.o
>   LD      .tmp_vmlinux.kallsyms1
>   KSYMS   .tmp_vmlinux.kallsyms1.S
>   AS      .tmp_vmlinux.kallsyms1.S
>   LD      .tmp_vmlinux.kallsyms2
>   KSYMS   .tmp_vmlinux.kallsyms2.S
>   AS      .tmp_vmlinux.kallsyms2.S
>   LD      vmlinux
>   BTFIDS  vmlinux
> FAILED: load BTF from vmlinux: Invalid argument
> make: *** [Makefile:1159: vmlinux] Error 255
> make: *** Deleting file 'vmlinux'

This was reported and addressed a month ago:

    https://lore.kernel.org/bpf/20220825171620.cioobudss6ovyrkc@altlinux.org/t/#m24a9de4b8cc11eb9c3bbed022487d6de0d42ea4b

In short if you don't need XDP you could possibly disable
CONFIG_DEBUG_INFO_BTF, otherwise you may have to rebuild the latest
pahole utility that seems to be involved in this. But I never faced
this issue so I can only recommend hints about things to look at,
and could be wrong.

Willy