From: Masahiro Yamada masahiroy@kernel.org
[ Upstream commit c5e6ae563c802c4d828d42e134af64004db2e58c ]
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 3939f3345050 ("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 --- arch/arc/Makefile | 13 ++++++++++++- arch/arc/boot/Makefile | 11 +---------- 2 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/arch/arc/Makefile b/arch/arc/Makefile index cf9da9aea12ac..578bdbbb0fa7f 100644 --- a/arch/arc/Makefile +++ b/arch/arc/Makefile @@ -102,11 +102,22 @@ libs-y += arch/arc/lib/ $(LIBGCC)
boot := arch/arc/boot
-boot_targets := uImage uImage.bin uImage.gz uImage.lzma +boot_targets := uImage.bin uImage.gz uImage.lzma
PHONY += $(boot_targets) $(boot_targets): vmlinux $(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+uimage-default-y := uImage.bin +uimage-default-$(CONFIG_KERNEL_GZIP) := uImage.gz +uimage-default-$(CONFIG_KERNEL_LZMA) := uImage.lzma + +PHONY += uImage +uImage: $(uimage-default-y) + @ln -sf $< $(boot)/uImage + @$(kecho) ' Image $(boot)/uImage is ready' + +CLEAN_FILES += $(boot)/uImage + archclean: $(Q)$(MAKE) $(clean)=$(boot) diff --git a/arch/arc/boot/Makefile b/arch/arc/boot/Makefile index 538b92f4dd253..3b1f8a69a89ef 100644 --- a/arch/arc/boot/Makefile +++ b/arch/arc/boot/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -targets := vmlinux.bin vmlinux.bin.gz uImage +targets := vmlinux.bin vmlinux.bin.gz
# uImage build relies on mkimage being availble on your host for ARC target # You will need to build u-boot for ARC, rename mkimage to arc-elf32-mkimage @@ -13,11 +13,6 @@ LINUX_START_TEXT = $$(readelf -h vmlinux | \ UIMAGE_LOADADDR = $(CONFIG_LINUX_LINK_BASE) UIMAGE_ENTRYADDR = $(LINUX_START_TEXT)
-suffix-y := bin -suffix-$(CONFIG_KERNEL_GZIP) := gz -suffix-$(CONFIG_KERNEL_LZMA) := lzma - -targets += uImage targets += uImage.bin targets += uImage.gz targets += uImage.lzma @@ -42,7 +37,3 @@ $(obj)/uImage.gz: $(obj)/vmlinux.bin.gz FORCE
$(obj)/uImage.lzma: $(obj)/vmlinux.bin.lzma FORCE $(call if_changed,uimage,lzma) - -$(obj)/uImage: $(obj)/uImage.$(suffix-y) - @ln -sf $(notdir $<) $@ - @echo ' Image $@ is ready'