On Sun, 19 Nov 2023 at 00:32, Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
>
> A common issue in Makefile is a race in parallel building.
>
> You need to be careful to prevent multiple threads from writing to the
> same file simultaneously.
>
> Commit 3939f3345050 ("ARM: 8418/1: add boot image dependencies to not
> generate invalid images") addressed such a bad scenario.
>
> A similar symptom occurs with the following command:
>
> $ make -j$(nproc) ARCH=arm64 Image vmlinuz.efi
> [ snip ]
> SORTTAB vmlinux
> OBJCOPY arch/arm64/boot/Image
> OBJCOPY arch/arm64/boot/Image
> AS arch/arm64/boot/zboot-header.o
> PAD arch/arm64/boot/vmlinux.bin
> GZIP arch/arm64/boot/vmlinuz
> OBJCOPY arch/arm64/boot/vmlinuz.o
> LD arch/arm64/boot/vmlinuz.efi.elf
> OBJCOPY arch/arm64/boot/vmlinuz.efi
>
> The log "OBJCOPY arch/arm64/boot/Image" is displayed twice.
>
> It indicates that two threads simultaneously enter arch/arm64/boot/
> and write to arch/arm64/boot/Image.
>
> It occasionally leads to a build failure:
>
> $ make -j$(nproc) ARCH=arm64 Image vmlinuz.efi
> [ snip ]
> SORTTAB vmlinux
> OBJCOPY arch/arm64/boot/Image
> PAD arch/arm64/boot/vmlinux.bin
> truncate: Invalid number: 'arch/arm64/boot/vmlinux.bin'
> make[2]: *** [drivers/firmware/efi/libstub/Makefile.zboot:13:
> arch/arm64/boot/vmlinux.bin] Error 1
> make[2]: *** Deleting file 'arch/arm64/boot/vmlinux.bin'
> make[1]: *** [arch/arm64/Makefile:163: vmlinuz.efi] Error 2
> make[1]: *** Waiting for unfinished jobs....
> make: *** [Makefile:234: __sub-make] Error 2
>
> vmlinuz.efi depends on Image, but such a dependency is not specified
> in arch/arm64/Makefile.
>
To clarify, this dependency /is/ specified in
arch/arm64/boot/Makefile, which is consumed by explicit make
invocations from arch/arm64/Makefile, and these may end up racing with
each other.
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
>
> arch/arm64/Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> index 4a1ad3248c2d..47ecc4cff9d2 100644
> --- a/arch/arm64/Makefile
> +++ b/arch/arm64/Makefile
> @@ -158,7 +158,7 @@ endif
>
> all: $(notdir $(KBUILD_IMAGE))
>
> -
> +vmlinuz.efi: Image
> Image vmlinuz.efi: vmlinux
> $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
>
> --
> 2.40.1
>
