From: Borislav Petkov <bp@xxxxxxx> When building randconfigs, the build fails at kernel compression stage due to missing lz4 on the system but CONFIG_KERNEL_LZ4 has been selected by randconfig. The result looks somethins like this: (cat arch/x86/boot/compressed/vmlinux.bin arch/x86/boot/compressed/vmlinux.relocs | lz4c -l -c1 stdin stdout && printf \334\141\301\001) > arch/x86/boot/compressed/vmlinux.bin.lz4 || (rm -f arch/x86/boot/compressed/vmlinux.bin.lz4 ; false) /bin/sh: 1: lz4c: not found make[2]: *** [arch/x86/boot/compressed/Makefile:143: arch/x86/boot/compressed/vmlinux.bin.lz4] Error 1 make[1]: *** [arch/x86/boot/Makefile:112: arch/x86/boot/compressed/vmlinux] Error 2 make: *** [arch/x86/Makefile:290: bzImage] Error 2 Fail the build much earlier by checking for lz4c presence before doing anything else. Signed-off-by: Borislav Petkov <bp@xxxxxxx> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cc: Michal Marek <michal.lkml@xxxxxxxxxxx> Cc: linux-kbuild@xxxxxxxxxxxxxxx --- Makefile | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Makefile b/Makefile index a0c32de80482..f91de649234b 100644 --- a/Makefile +++ b/Makefile @@ -788,6 +788,12 @@ KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections LDFLAGS_vmlinux += --gc-sections endif +ifdef CONFIG_KERNEL_LZ4 +ifeq ($(CONFIG_SHELL which lz4c),) +$(error "lz4 tool not found on this system but CONFIG_KERNEL_LZ4 enabled") +endif +endif + # arch Makefile may override CC so keep this after arch Makefile is included NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) -- 2.19.0.271.gfe8321ec057f