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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 3939f33450 ("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=loongarch vmlinux.efi vmlinuz.efi
[ snip ]
SORTTAB vmlinux
OBJCOPY arch/loongarch/boot/vmlinux.efi
OBJCOPY arch/loongarch/boot/vmlinux.efi
PAD arch/loongarch/boot/vmlinux.bin
GZIP arch/loongarch/boot/vmlinuz
OBJCOPY arch/loongarch/boot/vmlinuz.o
LD arch/loongarch/boot/vmlinuz.efi.elf
OBJCOPY arch/loongarch/boot/vmlinuz.efi
The log "OBJCOPY arch/loongarch/boot/vmlinux.efi" is displayed twice.
It indicates that two threads simultaneously enter arch/loongarch/boot/
and write to arch/loongarch/boot/vmlinux.efi.
It occasionally leads to a build failure:
$ make -j$(nproc) ARCH=loongarch vmlinux.efi vmlinuz.efi
[ snip ]
SORTTAB vmlinux
OBJCOPY arch/loongarch/boot/vmlinux.efi
PAD arch/loongarch/boot/vmlinux.bin
truncate: Invalid number: ‘arch/loongarch/boot/vmlinux.bin’
make[2]: *** [drivers/firmware/efi/libstub/Makefile.zboot:13:
arch/loongarch/boot/vmlinux.bin] Error 1
make[2]: *** Deleting file 'arch/loongarch/boot/vmlinux.bin'
make[1]: *** [arch/loongarch/Makefile:146: vmlinuz.efi] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:234: __sub-make] Error 2
vmlinuz.efi depends on vmlinux.efi, but such a dependency is not
specified in arch/loongarch/Makefile.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.