gcc15 compile 6.6.y kernel failed #12971

yihaodong1 · 2025-05-23T02:52:13Z

yihaodong1
May 23, 2025

the error is below

  CC      arch/x86/realmode/rm/wakemain.o
In file included from ./include/uapi/linux/posix_types.h:5,
                 from ./include/uapi/linux/types.h:14,
                 from ./include/linux/types.h:6,
                 from arch/x86/realmode/rm/wakeup.h:11,
                 from arch/x86/realmode/rm/wakemain.c:2:
./include/linux/stddef.h:11:9: error: cannot use keyword ‘false’ as enumeration constant
   11 |         false   = 0,
      |         ^~~~~
./include/linux/stddef.h:11:9: note: ‘false’ is a keyword with ‘-std=c23’ onwards
./include/linux/types.h:35:33: error: ‘bool’ cannot be defined via ‘typedef’
   35 | typedef _Bool                   bool;
      |                                 ^~~~
./include/linux/types.h:35:33: note: ‘bool’ is a keyword with ‘-std=c23’ onwards
./include/linux/types.h:35:1: warning: useless type name in empty declaration
   35 | typedef _Bool                   bool;
      | ^~~~~~~
  CC      arch/x86/mm/init.o

I assume that this is because gcc15 use -std=c23 as default, and I use command "make -n -j$(nproc) KCONFIG_CONFIG=Microsoft/config-wsl | sed 's/;/\n/g' | grep gcc |grep -v "std" | less" to find the compile command use default std, and its output is below

make[2]: *** No rule to make target 'vmlinux.a', needed by 'vmlinux.o'.  Stop.
make[1]: *** [/home/dyh/WSL2-Linux-Kernel/Makefile:1150: vmlinux_o] Error 2
make: *** [Makefile:234: __sub-make] Error 2
 { ./scripts/mkcompile_h "x86_64" "gcc (GCC) 15.1.1 20250425" "ld"
 gcc   -o arch/x86/tools/relocs arch/x86/tools/relocs_32.o arch/x86/tools/relocs_64.o arch/x86/tools/relocs_common.o
 printf '%s\n' 'savedcmd_arch/x86/tools/relocs := gcc   -o arch/x86/tools/relocs arch/x86/tools/relocs_32.o arch/x86/tools/relocs_64.o arch/x86/tools/relocs_common.o   ' > arch/x86/tools/.relocs.cmd
make -f ./scripts/Makefile.build obj=scripts/gcc-plugins \
 gcc   -o scripts/genksyms/genksyms scripts/genksyms/genksyms.o scripts/genksyms/parse.tab.o scripts/genksyms/lex.lex.o
 printf '%s\n' 'savedcmd_scripts/genksyms/genksyms := gcc   -o scripts/genksyms/genksyms scripts/genksyms/genksyms.o scripts/genksyms/parse.tab.o scripts/genksyms/lex.lex.o   ' > scripts/genksyms/.genksyms.cmd
            DESTDIR=/home/dyh/WSL2-Linux-Kernel/tools/bpf/resolve_btfids/libsubcmd/ AR="ar" CC="gcc" LD="ld" ARCH="x86" CROSS_COMPILE="" EXTRA_CFLAGS="" prefix= subdir= \
 gcc   -o scripts/mod/modpost scripts/mod/modpost.o scripts/mod/file2alias.o scripts/mod/sumversion.o scripts/mod/symsearch.o
 printf '%s\n' 'savedcmd_scripts/mod/modpost := gcc   -o scripts/mod/modpost scripts/mod/modpost.o scripts/mod/file2alias.o scripts/mod/sumversion.o scripts/mod/symsearch.o   ' > scripts/mod/.modpost.cmd
gcc /home/dyh/WSL2-Linux-Kernel/tools/objtool/objtool-in.o -lelf /home/dyh/WSL2-Linux-Kernel/tools/objtool/libsubcmd/libsubcmd.a   -o /home/dyh/WSL2-Linux-Kernel/tools/objtool/objtool
 gcc   -o drivers/accessibility/speakup/makemapdata drivers/accessibility/speakup/makemapdata.o
 printf '%s\n' 'savedcmd_drivers/accessibility/speakup/makemapdata := gcc   -o drivers/accessibility/speakup/makemapdata drivers/accessibility/speakup/makemapdata.o   ' > drivers/accessibility/speakup/.makemapdata.cmd
 gcc   -o drivers/accessibility/speakup/genmap drivers/accessibility/speakup/genmap.o
 printf '%s\n' 'savedcmd_drivers/accessibility/speakup/genmap := gcc   -o drivers/accessibility/speakup/genmap drivers/accessibility/speakup/genmap.o   ' > drivers/accessibility/speakup/.genmap.cmd

2025-05-23T02:52:45Z

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bot May 23, 2025

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0 replies

yihaodong1 · 2025-05-23T03:03:44Z

yihaodong1
May 23, 2025
Author

WslLogs-2025-05-23_10-58-21.zip
/question

0 replies

2025-05-23T03:04:23Z

github-actions[bot]
bot May 23, 2025

Diagnostic information

Found '/question', adding tag 'question'
.wslconfig found
Detected appx version: 2.4.11.0

0 replies

elsaco · 2025-05-23T06:29:20Z

elsaco
May 23, 2025

@yihaodong1 why are you trying to build the Linux kernel using C23 standard? While there is work in progress, the Linux kernel is not C23 compatible yet. Add a build flag, i.e. -std=gnu17 if using gcc15 ...or port the Linux kernel code to C23!

0 replies

yihaodong1 · 2025-05-23T06:44:32Z

yihaodong1
May 23, 2025
Author

@yihaodong1 why are you trying to build the Linux kernel using C23 standard? While there is work in progress, the Linux kernel is not C23 compatible yet. Add a build flag, i.e. -std=gnu17 if using gcc15 ...or port the Linux kernel code to C23!

I am using Arch ditro, and its gcc is gcc15 now. And I want to add the build flag, but did not find the suitable place😂

0 replies

yihaodong1 · 2025-07-12T11:21:05Z

yihaodong1
Jul 12, 2025
Author

use gcc-13, and make -CC=gcc-13

1 reply

biggestsonicfan Aug 16, 2025

For anyone who comes searching for this, gcc13 is no longer in the extra repo is only maintained in the aur user repos. I would not build wsl2 for use in production with this.

aswild · 2025-07-20T22:32:27Z

aswild
Jul 20, 2025

For reference, the upstream mainline "fix" for this is this commit: torvalds/linux@b3bee1e

Or on the 6.6.y branch, gregkh/linux@bc133e4 is part of 6.6.93.

This isn't exactly a "fix" because GCC 15 compatibility wasn't a thing back in 2023, but adding an explicit -std=gnu11 flag when building the x86 code does address this build error.

2 replies

biggestsonicfan Aug 17, 2025

Just an fyi

https://github.com/microsoft/WSL2-Linux-Kernel/blob/427645e3db3a8896714f22a3d3fe0c3f7b317ad4/Makefile#L560

-std=gnu11 is now included in the Makefile and I still get this error.

aswild Aug 20, 2025

The changes in question add -std=gnu11 to REALMODE_CFLAGS in arch/x86/Makefile (to match the top-level Makefile, which had had that flag for a while)

gcc15 compile 6.6.y kernel failed #12971

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yihaodong1 May 23, 2025

Replies: 7 comments · 3 replies

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yihaodong1 May 23, 2025 Author

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yihaodong1 Jul 12, 2025 Author

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aswild Jul 20, 2025

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biggestsonicfan Aug 17, 2025

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aswild Aug 20, 2025

yihaodong1
May 23, 2025

Replies: 7 comments 3 replies

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yihaodong1
May 23, 2025
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Jul 12, 2025
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aswild
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