Re: [PATCH net-next 3/3] net/mlx5: Apply devlink default eswitch mode during init

[Thomas Weißschuh]

On Thu, May 21, 2026 at 04:16:28PM +0300, Mark Bloch wrote:
(...)

> NIPA flagged this patch with a build_allmodconfig_warn failure:
> https://netdev-ctrl.bots.linux.dev/logs/build/1098506/14585935/build_allmodconfig_warn/
> 
> I do not see how this mlx5 patch is related to the reported issue,
> but I looked into it anyway.
> 
> After the kernel has been built once, the issue can be reproduced by rerunning sparse
> only on version.o, which filters out the unrelated noise. I had an older sparse installed,
> so I used a local copy:
> 
> rm -f arch/x86/boot/version.o
> make V=1 C=1 CHECK=/labhome/mbloch/bin/sparse arch/x86/boot/version.o
> 
> This gives the same error reported by NIPA:
> 
> ...
> ...
> make -f ./scripts/Makefile.vmlinux
> make -f ./scripts/Makefile.build obj=arch/x86/boot arch/x86/boot/bzImage
> make -f ./scripts/Makefile.build obj=arch/x86/boot/compressed arch/x86/boot/compressed/vmlinux
> # CC      arch/x86/boot/version.o
>   gcc -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5     -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version -c -o arch/x86/boot/version.o arch/x86/boot/version.c
> # CHECK   arch/x86/boot/version.c
>   /labhome/mbloch/bin/sparse -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise -Wno-return-void -Wno-unknown-attribute  -D__x86_64__ --arch=x86 -mlittle-endian -m64 -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5     -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version arch/x86/boot/version.c
> arch/x86/boot/version.c: note: in included file (through arch/x86/include/uapi/asm/bitsperlong.h, include/uapi/asm-generic/int-ll64.h, include/asm-generic/int-ll64.h, include/uapi/asm-generic/types.h, ...):
> ./include/asm-generic/bitsperlong.h:23:2: error: Inconsistent word size. Check asm/bitsperlong.h
> ./include/asm-generic/bitsperlong.h:27:33: error: static assertion failed: "Inconsistent word size. Check asm/bitsperlong.h"
> # cmd_gen_symversions_c arch/x86/boot/version.o
>   if nm arch/x86/boot/version.o 2>/dev/null | grep -q ' __export_symbol_'; then gcc -E -D__GENKSYMS__ -Wp,-MMD,arch/x86/boot/.version.o.d -nostdinc -I./arch/x86/include -I./arch/x86/include/generated -I./include -I./include -I./arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I./include/uapi -I./include/generated/uapi -include ./include/linux/compiler-version.h -include ./include/linux/kconfig.h -include ./include/linux/compiler_types.h -D__KERNEL__ -std=gnu11 -fms-extensions -m16 -g -Os -DDISABLE_BRANCH_PROFILING -D__DISABLE_EXPORTS -Wall -Wstrict-prototypes -march=i386 -mregparm=3 -fno-strict-aliasing -fomit-frame-pointer -fno-pic -mno-mmx -mno-sse -fcf-protection=none -ffreestanding -fno-stack-protector -Wno-address-of-packed-member -mpreferred-stack-boundary=2 -D_SETUP -fno-asynchronous-unwind-tables -Wimplicit-fallthrough=5     -DKBUILD_MODFILE='"arch/x86/boot/version"' -DKBUILD_BASENAME='"version"' -DKBUILD_MODNAME='"version"' -D__KBUILD_MODNAME=version arch/x86/boot/version.c | ./scripts/genksyms/genksyms    >> arch/x86/boot/.version.o.cmd; fi
> # LD      arch/x86/boot/setup.elf
>   ld -m elf_x86_64 -z noexecstack  -m elf_i386 -z noexecstack -T arch/x86/boot/setup.ld arch/x86/boot/a20.o arch/x86/boot/bioscall.o arch/x86/boot/cmdline.o arch/x86/boot/copy.o arch/x86/boot/cpu.o arch/x86/boot/cpuflags.o arch/x86/boot/cpucheck.o arch/x86/boot/early_serial_console.o arch/x86/boot/edd.o arch/x86/boot/header.o arch/x86/boot/main.o arch/x86/boot/memory.o arch/x86/boot/pm.o arch/x86/boot/pmjump.o arch/x86/boot/printf.o arch/x86/boot/regs.o arch/x86/boot/string.o arch/x86/boot/tty.o arch/x86/boot/video.o arch/x86/boot/video-mode.o arch/x86/boot/version.o arch/x86/boot/video-vga.o arch/x86/boot/video-vesa.o arch/x86/boot/video-bios.o -o arch/x86/boot/setup.elf
> # OBJCOPY arch/x86/boot/setup.bin
>   objcopy  -O binary arch/x86/boot/setup.elf arch/x86/boot/setup.bin
> # BUILD   arch/x86/boot/bzImage
>   (dd if=arch/x86/boot/setup.bin bs=4k conv=sync status=none; cat arch/x86/boot/vmlinux.bin) >arch/x86/boot/bzImage
> mkdir -p ./arch/x86_64/boot
> ln -fsn ../../x86/boot/bzImage ./arch/x86_64/boot/bzImage
> 
> To me this looks like sparse is getting a conflicting set of flags.
> The command line contains both "-D__x86_64__ -m64" and "-m16 -march=i386 -D_SETUP".
> 
> I confirmed that the following patch "fixes" the issue, but I do not know whether
> this is the right fix. This area is outside my comfort zone, so it would be
> helpful if someone more familiar with the x86 build/sparse flow could take a
> look:
> 
> diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
> index 3f9fb3698d66..80923864f6f9 100644
> --- a/arch/x86/boot/Makefile
> +++ b/arch/x86/boot/Makefile
> @@ -71,6 +71,10 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE
> 
>  SETUP_OBJS = $(addprefix $(obj)/,$(setup-y))
> 
> +realmode-checkflags-$(CONFIG_X86_64) := -m32 -U__x86_64__ -D__i386__
> +REALMODE_CHECKFLAGS := $(filter-out -m64 -D__x86_64__,$(CHECKFLAGS)) $(realmode-checkflags-y)
> +$(SETUP_OBJS): CHECKFLAGS := $(REALMODE_CHECKFLAGS)
> +
>  sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|efi.._stub_entry\|efi\(32\)\?_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|_e\?data\|_e\?sbat\|z_.*\)$$/\#define ZO_\2 0x\1/p'
> 
>  quiet_cmd_zoffset = ZOFFSET $@
> diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
> index a0fb39abc5c8..341b0ff20c3d 100644
> --- a/arch/x86/realmode/rm/Makefile
> +++ b/arch/x86/realmode/rm/Makefile
> @@ -29,6 +29,10 @@ targets      += $(realmode-y)
> 
>  REALMODE_OBJS = $(addprefix $(obj)/,$(realmode-y))
> 
> +realmode-checkflags-$(CONFIG_X86_64) := -m32 -U__x86_64__ -D__i386__
> +REALMODE_CHECKFLAGS := $(filter-out -m64 -D__x86_64__,$(CHECKFLAGS)) $(realmode-checkflags-y)
> +$(REALMODE_OBJS): CHECKFLAGS := $(REALMODE_CHECKFLAGS)
> +

The idea looks good, we do something similar for the 32-bit vDSO:

arch/x86/entry/vdso/vdso32/Makefile

CHECKFLAGS := $(subst -m64,-m32,$(CHECKFLAGS))
CHECKFLAGS := $(subst -D__x86_64__,-D__i386__,$(CHECKFLAGS))

It seems the same kind of substitution would work here.
We can add a helper function to arch/x86/Makefile and
use that also for the compat vDSO.

I am wondering why this didn't show up before.
Are you going to send a patch or should I?


Thomas