Arch Linux

jb.1234abcd

Member

Registered: 2013-10-14

Posts: 54

[ANSWERED] kernel config warning - symbol value 'm' invalid for MCTP

$ uname -a
Linux r61i 5.15.7-arch1-1 #1 SMP PREEMPT Wed, 08 Dec 2021 14:33:16 +0000 x86_64 GNU/Linux

Compilation of linux-mainline-git kernel.
$ git status
HEAD detached at v5.16-rc5
nothing to commit, working tree clean
$
Tried 'make oldconfig' (based on a provided copy of /proc/config.gz).
$ make distclean
$ zcat /proc/config.gz > .config
$ make oldconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/confdata.o
  HOSTCC  scripts/kconfig/expr.o
  LEX     scripts/kconfig/lexer.lex.c
  YACC    scripts/kconfig/parser.tab.[ch]
  HOSTCC  scripts/kconfig/lexer.lex.o
  HOSTCC  scripts/kconfig/menu.o
  HOSTCC  scripts/kconfig/parser.tab.o
  HOSTCC  scripts/kconfig/preprocess.o
  HOSTCC  scripts/kconfig/symbol.o
  HOSTCC  scripts/kconfig/util.o
  HOSTLD  scripts/kconfig/conf
.config:1968:warning: symbol value 'm' invalid for MCTP
*
* Restart config...
*
*
...
*
* MCTP core protocol support
*
MCTP core protocol support (MCTP) [N/y/?] (NEW) <hit Enter>
...
#
# configuration written to .config
#
$ grep MCTP .config
# CONFIG_MCTP is not set

I verified:
$ zgrep MCTP /proc/config.gz
CONFIG_MCTP=m
$ grep MCTP arch/x86/configs/x86_64_defconfig
$

So, a problem with ArchLinux kernel config file ?

More trouble, with compilation.
$ make
...
  AR      fs/built-in.a
# make modules_install
sed: can't read modules.order: No such file or directory
make: *** [Makefile:1479: __modinst_pre] Error 2
#

Tried 'make localmodconfig' (based on /proc/config.gz):
$ make distclean
$ make localmodconfig
No problem with ArchLinux kernel config file.
Good compilation and OS run.

***
For comparison, I switched to a mainline production kernel.
Compilation of linux-mainline-git kernel.
$ git status
HEAD detached at v5.15
nothing to commit, working tree clean
$
Tried 'make oldconfig' (based on a provided copy of /proc/config.gz).
$ make distclean
$ zcat /proc/config.gz > .config
$ make oldconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/confdata.o
  HOSTCC  scripts/kconfig/expr.o
  LEX     scripts/kconfig/lexer.lex.c
  YACC    scripts/kconfig/parser.tab.[ch]
  HOSTCC  scripts/kconfig/lexer.lex.o
  HOSTCC  scripts/kconfig/menu.o
  HOSTCC  scripts/kconfig/parser.tab.o
  HOSTCC  scripts/kconfig/preprocess.o
  HOSTCC  scripts/kconfig/symbol.o
  HOSTCC  scripts/kconfig/util.o
  HOSTLD  scripts/kconfig/conf
*
* Restart config...
*
...
# configuration written to .config
$
Note: no 'make oldconfig' config error on production kernel 5.15 .
$ grep MCTP .config
CONFIG_MCTP=m
$
Note: CONFIG_MCTP=m
I verified:
$ zgrep MCTP /proc/config.gz
CONFIG_MCTP=m
$ grep MCTP arch/x86/configs/x86_64_defconfig
$
$ make
...
  AR      fs/built-in.a
$
# make modules_install
sed: can't read modules.order: No such file or directory
make: *** [Makefile:1501: __modinst_pre] Error 2
#

So, the behavior of 'make oldconfig' based on ArchLinux's kernel config file
(/proc/config.gz) is different on production kernel 5.15 (good) and
testing kernel 5.16-rc5 (bad).
Kernel compilation fails for both kernels anyway.

ANSWERED:
The reason for 5.16-rc5 config error "The config:1968:warning: symbol value 'm' invalid for MCTP":
the developer of MCTP changed the net/mctp/Kconfig from type tristate to bool
somewhere between 5.15.0 and 5.16-rc5 while Archlinux config file stays set to CONFIG_MCTP=m.

The reson for compilation failure was a missing tool program on my host.

Last edited by jb.1234abcd (2021-12-19 14:44:59)