On Wed, Nov 11, 2020 at 12:55 AM Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> wrote: > > On Tue, Nov 10, 2020 at 08:57:51PM -0800, Andrii Nakryiko wrote: > > On Tue, Nov 10, 2020 at 8:46 AM Jean-Philippe Brucker > > <jean-philippe@xxxxxxxxxx> wrote: > > > > > > Cleaning a partial build can fail if the output directory for libbpf > > > wasn't created: > > > > > > $ make -C tools/bpf/bpftool O=/tmp/bpf clean > > > /bin/sh: line 0: cd: /tmp/bpf/libbpf/: No such file or directory > > > tools/scripts/Makefile.include:17: *** output directory "/tmp/bpf/libbpf/" does not exist. Stop. > > > make: *** [Makefile:36: /tmp/bpf/libbpf/libbpf.a-clean] Error 2 > > > > > > As a result make never gets around to clearing the leftover objects. Add > > > the libbpf output directory as clean dependency to ensure clean always > > > succeeds (similarly to the "descend" macro). The directory is later > > > removed by the clean recipe. > > > > > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > > > --- > > > tools/bpf/bpftool/Makefile | 8 +++++--- > > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > > > diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile > > > index f60e6ad3a1df..1358c093b812 100644 > > > --- a/tools/bpf/bpftool/Makefile > > > +++ b/tools/bpf/bpftool/Makefile > > > @@ -27,11 +27,13 @@ LIBBPF = $(LIBBPF_PATH)libbpf.a > > > > > > BPFTOOL_VERSION ?= $(shell make -rR --no-print-directory -sC ../../.. kernelversion) > > > > > > -$(LIBBPF): FORCE > > > - $(if $(LIBBPF_OUTPUT),@mkdir -p $(LIBBPF_OUTPUT)) > > > +$(LIBBPF_OUTPUT): > > > + $(QUIET_MKDIR)mkdir -p $@ > > > + > > > +$(LIBBPF): FORCE | $(LIBBPF_OUTPUT) > > > $(Q)$(MAKE) -C $(BPF_DIR) OUTPUT=$(LIBBPF_OUTPUT) $(LIBBPF_OUTPUT)libbpf.a > > > > > > -$(LIBBPF)-clean: > > > +$(LIBBPF)-clean: $(LIBBPF_OUTPUT) > > > > shouldn't this be `| $(LIBBPF_OUTPUT)` ? > > It wouldn't have any effect here. Order-only prerequisites tell make to > only build the prerequisite before the target, but not to update the > target if the prerequisite was updated. Because $(LIBBPF)-clean is not a > file, the recipe is always run and adding the | doesn't make a difference. I know. I wanted it just for consistency, because everything after | means "make sure it's completed, but it's not my direct input". But I'm ok either way, it's not that important. Also $(LIBBPF)-clean and $(LIBBPF_BOOTSTRAP)-clean should be .PHONY targets, but then again in practice won't matter, because unlikely that we'll have such files. Would be nice to follow up with a fix, but I'll apply your patch set as is. > > Thanks, > Jean
