Re: [PATCH bpf] tools/bpf: build: make sure resolve_btfids cleans up after itself

["Toke Høiland-Jørgensen" <toke@redhat.com>]

Jiri Olsa <jolsa@redhat.com> writes:

> On Tue, Sep 01, 2020 at 04:43:43PM +0200, Toke Høiland-Jørgensen wrote:
>> The new resolve_btfids tool did not clean up the feature detection folder
>> on 'make clean', and also was not called properly from the clean rule in
>> tools/make/ folder on its 'make clean'. This lead to stale objects being
>> left around, which could cause feature detection to fail on subsequent
>> builds.
>> 
>> Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
>> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
>> ---
>>  tools/bpf/Makefile                | 4 ++--
>>  tools/bpf/resolve_btfids/Makefile | 1 +
>>  2 files changed, 3 insertions(+), 2 deletions(-)
>> 
>> diff --git a/tools/bpf/Makefile b/tools/bpf/Makefile
>> index 0a6d09a3e91f..39bb322707b4 100644
>> --- a/tools/bpf/Makefile
>> +++ b/tools/bpf/Makefile
>> @@ -38,7 +38,7 @@ FEATURE_TESTS = libbfd disassembler-four-args
>>  FEATURE_DISPLAY = libbfd disassembler-four-args
>>  
>>  check_feat := 1
>> -NON_CHECK_FEAT_TARGETS := clean bpftool_clean runqslower_clean
>> +NON_CHECK_FEAT_TARGETS := clean bpftool_clean runqslower_clean resolve_btfids_clean
>>  ifdef MAKECMDGOALS
>>  ifeq ($(filter-out $(NON_CHECK_FEAT_TARGETS),$(MAKECMDGOALS)),)
>>    check_feat := 0
>> @@ -89,7 +89,7 @@ $(OUTPUT)bpf_exp.lex.c: $(OUTPUT)bpf_exp.yacc.c
>>  $(OUTPUT)bpf_exp.yacc.o: $(OUTPUT)bpf_exp.yacc.c
>>  $(OUTPUT)bpf_exp.lex.o: $(OUTPUT)bpf_exp.lex.c
>>  
>> -clean: bpftool_clean runqslower_clean
>> +clean: bpftool_clean runqslower_clean resolve_btfids_clean
>>  	$(call QUIET_CLEAN, bpf-progs)
>>  	$(Q)$(RM) -r -- $(OUTPUT)*.o $(OUTPUT)bpf_jit_disasm $(OUTPUT)bpf_dbg \
>>  	       $(OUTPUT)bpf_asm $(OUTPUT)bpf_exp.yacc.* $(OUTPUT)bpf_exp.lex.*
>> diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
>> index a88cd4426398..fe8eb537688b 100644
>> --- a/tools/bpf/resolve_btfids/Makefile
>> +++ b/tools/bpf/resolve_btfids/Makefile
>> @@ -80,6 +80,7 @@ libbpf-clean:
>>  clean: libsubcmd-clean libbpf-clean fixdep-clean
>>  	$(call msg,CLEAN,$(BINARY))
>>  	$(Q)$(RM) -f $(BINARY); \
>> +	$(RM) -rf $(if $(OUTPUT),$(OUTPUT),.)/feature; \
>
> I forgot this one.. thanks for fixing this

You're welcome - it was a bit frustrating to track down, but a simple
fix once I figured out what was going on.

BTW, there's still an issue that a 'make clean' in the toplevel kernel
dir will not clean up this feature dir, so if someone doesn't know to do
'cd tools/bpf && make clean' the main build may still break (I happened
upon this because my main kernel build broke :/). Couldn't figure out
how to convince make to fix that, so if you could take a look that would
be great! :)

-Toke