4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> commit e00d8880481497474792d28c14479a9fb6752046 upstream. Commit c3ff2a5193fa ("powerpc/32: add stack protector support") caused kernel panic on PowerPC when an external module is used with CONFIG_STACKPROTECTOR because the 'prepare' target was not executed for the external module build. Commit e07db28eea38 ("kbuild: fix single target build for external module") turned it into a build error because the 'prepare' target is now executed but the 'prepare0' target is missing for the external module build. External module on arm/arm64 with CONFIG_STACKPROTECTOR_PER_TASK is also broken in the same way. Move 'PHONY += prepare0' to the common place. GNU Make is fine with missing rule for phony targets. I also removed the comment which is wrong irrespective of this commit. I minimize the change so it can be easily backported to 4.20.x To fix v4.20, please backport e07db28eea38 ("kbuild: fix single target build for external module"), and then this commit. Link: https://bugzilla.kernel.org/show_bug.cgi?id=201891 Fixes: e07db28eea38 ("kbuild: fix single target build for external module") Fixes: c3ff2a5193fa ("powerpc/32: add stack protector support") Fixes: 189af4657186 ("ARM: smp: add support for per-task stack canaries") Fixes: 0a1213fa7432 ("arm64: enable per-task stack canaries") Cc: linux-stable <stable@xxxxxxxxxxxxxxx> # v4.20 Reported-by: Samuel Holland <samuel@xxxxxxxxxxxx> Reported-by: Alexey Kardashevskiy <aik@xxxxxxxxx> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Tested-by: Alexey Kardashevskiy <aik@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/Makefile +++ b/Makefile @@ -967,6 +967,7 @@ ifdef CONFIG_STACK_VALIDATION endif endif +PHONY += prepare0 ifeq ($(KBUILD_EXTMOD),) core-y += kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/ @@ -1075,8 +1076,7 @@ scripts: scripts_basic scripts_dtc asm-g # archprepare is used in arch Makefiles and when processed asm symlink, # version.h and scripts_basic is processed / created. -# Listed in dependency order -PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3 +PHONY += prepare archprepare prepare1 prepare2 prepare3 # prepare3 is used to check if we are building in a separate output directory, # and if so do: