4.9-stable review patch. If anyone has any objections, please let me know.
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From: Masahiro Yamada yamada.masahiro@socionext.com
[ Upstream commit 9c2af1c7377a8a6ef86e5cabf80978f3dbbb25c0 ]
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: Masahiro Yamada yamada.masahiro@socionext.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- scripts/Kbuild.include | 3 +++ 1 file changed, 3 insertions(+)
--- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -394,3 +394,6 @@ endif endef # ############################################################################### + +# delete partially updated (i.e. corrupted) files on error +.DELETE_ON_ERROR: