On Thu, Jan 30, 2020 at 12:38:32AM -0800, Yulia Kartseva wrote: > From: Julia Kartseva <hex@xxxxxx> I don't think you need the 'From: ' line if you are the sender of patch. > > Fixes: 9c01546d26d2 ("tools/bpf: Add runqslower tool to tools/bpf") > Signed-off-by: Julia Kartseva <hex@xxxxxx> > Acked-by: Andrii Nakryiko <andriin@xxxxxx> These tags should be placed after the commit message. > > Fix undefined reference linker errors when building runqslower with > gcc 7.4.0 on Ubuntu 18.04. > The issue is with misplaced -lelf, -lz options in Makefile: > $(Q)$(CC) $(CFLAGS) -lelf -lz $^ -o $@ > > -lelf, -lz options should follow the list of target dependencies: > $(Q)$(CC) $(CFLAGS) $^ -lelf -lz -o $@ > or after substitution > cc -g -Wall runqslower.o libbpf.a -lelf -lz -o runqslower > > The current order of gcc params causes failure in libelf symbols resolution, > e.g. undefined reference to `elf_memory' > --- > tools/bpf/runqslower/Makefile | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/bpf/runqslower/Makefile b/tools/bpf/runqslower/Makefile > index 0c021352b..87eae5be9 100644 > --- a/tools/bpf/runqslower/Makefile > +++ b/tools/bpf/runqslower/Makefile > @@ -41,7 +41,7 @@ clean: > > $(OUTPUT)/runqslower: $(OUTPUT)/runqslower.o $(BPFOBJ) > $(call msg,BINARY,$@) > - $(Q)$(CC) $(CFLAGS) -lelf -lz $^ -o $@ > + $(Q)$(CC) $(CFLAGS) $^ -lelf -lz -o $@ > > $(OUTPUT)/runqslower.o: runqslower.h $(OUTPUT)/runqslower.skel.h \ > $(OUTPUT)/runqslower.bpf.o > -- > 2.17.1 >