Hi, 本当に申し訳ありません, I got sidetracked and completely forgot about it. I actually still have my old tree with the suggested changes for v2. On Tue, 9 Apr 2019 at 11:01, Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> wrote: > > Hi. > > On Mon, Apr 8, 2019 at 5:03 PM Wiebe, Wladislav (Nokia - DE/Ulm) > <wladislav.wiebe@xxxxxxxxx> wrote: > > > > Hi! > > > > On 07.04.2019 11:04, Masahiro Yamada wrote: > > > (+CC Jonas Gorski) > > > > > > > > > On Tue, Mar 26, 2019 at 6:58 PM Wiebe, Wladislav (Nokia - DE/Ulm) > > > <wladislav.wiebe@xxxxxxxxx> wrote: > > >> > > >> Commit ea837f1c0503 ("kbuild: make modpost processing configurable") > > >> was intended to give KBUILD_MODPOST_WARN flexibility to be configurable. > > >> Right now KBUILD_MODPOST_WARN gets just ignored when KBUILD_EXTMOD is > > >> set which happens per default when building modules out of the tree. > > >> > > >> This change gives the opportunity to define module build behaving also > > >> in case of out of tree builds and default will become exit on error. > > >> Errors which can be detected by the build should be trapped out of the box > > >> there, unless somebody wants to notice broken stuff later at runtime. > > > > > > If an external module refers to a symbol > > > provided by another external module, > > > this patch will turn the warning into the error by default, > > > which is probably a bad idea. > > > > Indeed, exactly this should happen. You should fix your external module > > dependencies by providing their symbols. Please use e.g. > > KBUILD_EXTRA_SYMBOLS instead of converting errors to warning and hoping > > that things will work. > > I know this option. > What I want to say is, this patch changes the behavior, and > may annoy some people. > > > Or how do you want to make sure module A still > > delivers all symbols needed by module B after an update/changes? > > Manually comparing the logs after an update or waiting until it turns > > out broken during run-time? I wouldn't say this is a good idea :-) > > OK, so the commit log should record both the behavior change > and workarounds. > > - If an external module being built refers to symbols > in another external module, Kbuild previously showed a warning, > but going forward it will turn it into an error. > > - To work around this, you should pass a symbol table via KBUILD_EXTRA_SYMBOLS, > or KBUILD_EXTRA_SYMBOLS=1 to turn the error into a warning. This sounds like a good middle ground. When you do the effort of setting KBUILD_EXTRA_SYMBOLS, you are likely interested in proper dependency resolution and being notified if it fails. I would probably still use KBUILD_MODPOST_WARN=0 to force the warnings as errors, to have it as the central switch for the behaviour. So the behaviour would then become - If KBUILD_MODPOST_WARN is set to any value, set -w accordingly - else, set -w only when building for an external module and KBUILD_EXTRA_SYMBOLS is empty or ifdef KBUILD_MODPOST_WARN KBUILD_MODPOST_WARN:=$(filter-out 0,$(KBUILD_MODPOST_WARN)) else KBUILD_MODPOST_WARN:=$(if $(KBUILD_EXTMOD),$(if $(KBUILD_EXTRA_SYMBOLS),,1)) endif (completely untested) Regards Jonas