Hi Borislav, On Thu, Oct 11, 2018 at 7:23 AM Borislav Petkov <bp@xxxxxxxxx> wrote: > > 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 So, the cause of the failure is clear enough from the build log. It is weird to check only lz4c. If CONFIG_KERNEL_LZO is enabled, but lzop is not installed, I see this log LZO arch/x86/boot/compressed/vmlinux.bin.lzo /bin/sh: 1: lzop: not found It is still clear what to do, though. > 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. Is it necessary to check this earlier? If you get this error, you just need to install the tool. Then, you can re-run the incremental build. BTW, this patch has a drawback. [1] Enable CONFIG_KERNEL_LZ4 on the system without lz4c installed [2] Run 'make' and you will get the error "lz4 tool not found on this system but CONFIG_KERNEL_LZ4 enabled" [3] Run 'make menuconfig' and switch from CONFIG_KERNEL_LZ4 to CONFIG_KERNEL_GZIP [4] Run 'make' and you will still get the same error even after you have chosen to use GZIP instead of LZ4. > 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 > -- Best Regards Masahiro Yamada