Masahiro Yamada ca2fc0dc1c ARC: build: move symlink creation to arch/arc/Makefile to avoid race ... [ Upstream commit c5e6ae563c ] If you run 'make uImage uImage.gz' with the parallel option, uImage.gz will be created by two threads simultaneously. This is because arch/arc/Makefile does not specify the dependency between uImage and uImage.gz. Hence, GNU Make assumes they can be built in parallel. One thread descends into arch/arc/boot/ to create uImage, and another to create uImage.gz. Please notice the same log is displayed twice in the following steps: $ export CROSS_COMPILE=<your-arc-compiler-prefix> $ make -s ARCH=arc defconfig $ make -j$(nproc) ARCH=arc uImage uImage.gz [ snip ] LD vmlinux SORTTAB vmlinux SYSMAP System.map OBJCOPY arch/arc/boot/vmlinux.bin OBJCOPY arch/arc/boot/vmlinux.bin GZIP arch/arc/boot/vmlinux.bin.gz GZIP arch/arc/boot/vmlinux.bin.gz UIMAGE arch/arc/boot/uImage.gz UIMAGE arch/arc/boot/uImage.gz Image Name: Linux-5.10.0-rc4-00003-g62f23044 Created: Sun Nov 22 02:52:26 2020 Image Type: ARC Linux Kernel Image (gzip compressed) Data Size: 2109376 Bytes = 2059.94 KiB = 2.01 MiB Load Address: 80000000 Entry Point: 80004000 Image arch/arc/boot/uImage is ready Image Name: Linux-5.10.0-rc4-00003-g62f23044 Created: Sun Nov 22 02:52:26 2020 Image Type: ARC Linux Kernel Image (gzip compressed) Data Size: 2815455 Bytes = 2749.47 KiB = 2.69 MiB Load Address: 80000000 Entry Point: 80004000 This is a race between the two threads trying to write to the same file arch/arc/boot/uImage.gz. This is a potential problem that can generate a broken file. I fixed a similar problem for ARM by commit 3939f33450 ("ARM: 8418/1: add boot image dependencies to not generate invalid images"). I highly recommend to avoid such build rules that cause a race condition. Move the uImage rule to arch/arc/Makefile. Another strangeness is that arch/arc/boot/Makefile compares the timestamps between $(obj)/uImage and $(obj)/uImage.*: $(obj)/uImage: $(obj)/uImage.$(suffix-y) @ln -sf $(notdir $<) $@ @echo ' Image $@ is ready' This does not work as expected since $(obj)/uImage is a symlink. The symlink should be created in a phony target rule. I used $(kecho) instead of echo to suppress the message 'Image arch/arc/boot/uImage is ready' when the -s option is given. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-01-19 18:26:14 +01:00
..
boot	ARC: build: move symlink creation to arch/arc/Makefile to avoid race	2021-01-19 18:26:14 +01:00
configs	ARC: [plat-hsdk]: Enable on-boardi SPI ADC IC	2019-10-22 09:58:29 -07:00
include	arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed	2020-12-02 08:49:50 +01:00
kernel	ARC: stack unwinding: don't assume non-current task is sleeping	2020-12-16 10:56:55 +01:00
lib	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
mm	dma-mapping updates for 5.4:	2019-09-19 13:27:23 -07:00
oprofile	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
plat-axs10x	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
plat-eznps	irqchip/eznps: Fix build error for !ARC700 builds	2020-09-17 13:47:47 +02:00
plat-hsdk	arc: plat-hsdk: fix kconfig dependency warning when !RESET_CONTROLLER	2020-10-29 09:57:47 +01:00
plat-sim	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
plat-tb10x	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333	2019-06-05 17:37:06 +02:00
Kbuild	treewide: Add SPDX license identifier - Kbuild	2019-05-30 11:32:33 -07:00
Kconfig	dma-mapping updates for Linux 5.3	2019-07-12 15:13:55 -07:00
Kconfig.debug	Kconfig: consolidate the "Kernel hacking" menu	2018-08-02 08:06:48 +09:00
Makefile	ARC: build: move symlink creation to arch/arc/Makefile to avoid race	2021-01-19 18:26:14 +01:00