• Masahiro Yamada's avatar
    kbuild: add .DELETE_ON_ERROR special target · 69383cdc
    Masahiro Yamada authored
    [ Upstream commit 9c2af1c7 ]
    
    If Make gets a fatal signal while a shell is executing, it may delete
    the target file that the recipe was supposed to update.  This is needed
    to make sure that it is remade from scratch when Make is next run; if
    Make is interrupted after the recipe has begun to write the target file,
    it results in an incomplete file whose time stamp is newer than that
    of the prerequisites files.  Make automatically deletes the incomplete
    file on interrupt unless the target is marked .PRECIOUS.
    
    The situation is just the same as when the shell fails for some reasons.
    Usually when a recipe line fails, if it has changed the target file at
    all, the file is corrupted, or at least it is not completely updated.
    Yet the file’s time stamp says that it is now up to date, so the next
    time Make runs, it will not try to update that file.
    
    However, Make does not cater to delete the incomplete target file in
    this case.  We need to add .DELETE_ON_ERROR somewhere in the Makefile
    to request it.
    
    scripts/Kbuild.include seems a suitable place to add it because it is
    included from almost all sub-makes.
    
    Please note .DELETE_ON_ERROR is not effective for phony targets.
    
    The external module building should never ever touch the kernel tree.
    The following recipe fails if include/generated/autoconf.h is missing.
    However, include/config/auto.conf is not deleted since it is a phony
    target.
    
     PHONY += include/config/auto.conf
    
     include/config/auto.conf:
             $(Q)test -e include/generated/autoconf.h -a -e $@ || (          \
             echo >&2;                                                       \
             echo >&2 "  ERROR: Kernel configuration is invalid.";           \
             echo >&2 "         include/generated/autoconf.h or $@ are missing.";\
             echo >&2 "         Run 'make oldconfig && make prepare' on kernel src to fix it."; \
             echo >&2 ;                                                      \
             /bin/false)
    Signed-off-by: 's avatarMasahiro Yamada <yamada.masahiro@socionext.com>
    Signed-off-by: 's avatarSasha Levin <alexander.levin@microsoft.com>
    Signed-off-by: 's avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    69383cdc
Kbuild.include 15.3 KB