Re: [PATCH bpf v2 2/2] samples/{bpf,hid}: fix broken vmlinux path for VMLINUX_BTF

[Benjamin Tissoires]

On Jan 24 2025, Andrii Nakryiko wrote:
> On Thu, Jan 23, 2025 at 12:20 AM Jinghao Jia <jinghao7@xxxxxxxxxxxx> wrote:
> >
> > Commit 13b25489b6f8 ("kbuild: change working directory to external
> > module directory with M=") changed kbuild working directory of bpf and
> > hid samples to samples/{bpf,hid}, which broke the vmlinux path for
> > VMLINUX_BTF, as the Makefiles assume the current work directory to be
> > the kernel output directory and use a relative path (i.e., ./vmlinux):
> >
> >   Makefile:316: *** Cannot find a vmlinux for VMLINUX_BTF at any of "  /path/to/linux/samples/bpf/vmlinux", build the kernel or set VMLINUX_BTF like "VMLINUX_BTF=/sys/kernel/btf/vmlinux" or VMLINUX_H variable.  Stop.
> >
> > Correctly refer to the kernel output directory using $(objtree).
> >
> > Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=")
> > Tested-by: Ruowen Qin <ruqin@xxxxxxxxxx>
> > Signed-off-by: Jinghao Jia <jinghao7@xxxxxxxxxxxx>
> > ---
> >  samples/bpf/Makefile | 2 +-
> >  samples/hid/Makefile | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> 
> can you please split samples/bpf from samples/hid changes, so we can
> land samples/bpf fix through bpf-next tree independently from other
> changes?

FWIW, I don't mind if this goes through the bpf-next tree all at once.

Acked-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>

Cheers,
Benjamin

> 
> pw-bot: cr
> 
> > diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> > index 96a05e70ace3..f5865fbbae62 100644
> > --- a/samples/bpf/Makefile
> > +++ b/samples/bpf/Makefile
> > @@ -307,7 +307,7 @@ $(obj)/$(TRACE_HELPERS): TPROGS_CFLAGS := $(TPROGS_CFLAGS) -D__must_check=
> >
> >  VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux))                                \
> >                      $(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \
> > -                    $(abspath ./vmlinux)
> > +                    $(abspath $(objtree)/vmlinux)
> >  VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
> >
> >  $(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
> > diff --git a/samples/hid/Makefile b/samples/hid/Makefile
> > index 69159c81d045..db5a077c77fc 100644
> > --- a/samples/hid/Makefile
> > +++ b/samples/hid/Makefile
> > @@ -164,7 +164,7 @@ $(obj)/hid_surface_dial.o: $(obj)/hid_surface_dial.skel.h
> >
> >  VMLINUX_BTF_PATHS ?= $(abspath $(if $(O),$(O)/vmlinux))                                \
> >                      $(abspath $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux)) \
> > -                    $(abspath ./vmlinux)
> > +                    $(abspath $(objtree)/vmlinux)
> >  VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
> >
> >  $(obj)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
> > --
> > 2.48.1
> >