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| author | Masahiro Yamada <masahiroy@kernel.org> | 2020-11-21 22:36:55 +0300 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2020-12-02 04:24:05 +0300 |
| commit | c5e6ae563c802c4d828d42e134af64004db2e58c (patch) | |
| tree | de78a2bea7506d8d91cb37b8967c60afd2a8bcfc /arch/arc/boot | |
| parent | 0cfccb3c04934cdef42ae26042139f16e805b5f7 (diff) | |
| download | linux-c5e6ae563c802c4d828d42e134af64004db2e58c.tar.xz | |
ARC: build: move symlink creation to arch/arc/Makefile to avoid race
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>
Diffstat (limited to 'arch/arc/boot')
| -rw-r--r-- | arch/arc/boot/Makefile | 11 |
1 files changed, 1 insertions, 10 deletions
diff --git a/arch/arc/boot/Makefile b/arch/arc/boot/Makefile index 538b92f4dd25..3b1f8a69a89e 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' |