Re: [PATCH 1/1] perf bpf: Check that the minimal vmlinux.h installed is the latest one

[Ian Rogers]

On Sat, Feb 24, 2024 at 7:48 AM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> When building BPF skels perf will, by default, install a minimalistic
> vmlinux.h file with the types needed by the BPF skels in
> tools/perf/util/bpf_skel/ in its build directory.
>
> When 29d16de26df17e94 ("perf augmented_raw_syscalls.bpf: Move 'struct
> timespec64' to vmlinux.h") was added, a type used in the augmented_raw_syscalls
> BPF skel, 'struct timespec64' was not found when building from a pre-existing
> build directory, because the vmlinux.h there didn't contain that type,
> ending up with this error, spotted in linux-next:
>
>     CLANG   /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o
>   util/bpf_skel/augmented_raw_syscalls.bpf.c:329:15: error: invalid application of 'sizeof' to an incomplete type 'struct timespec64'
>     329 |         __u32 size = sizeof(struct timespec64);
>         |                      ^     ~~~~~~~~~~~~~~~~~~~
>   util/bpf_skel/augmented_raw_syscalls.bpf.c:329:29: note: forward declaration of 'struct timespec64'
>     329 |         __u32 size = sizeof(struct timespec64);
>         |                                    ^
>   util/bpf_skel/augmented_raw_syscalls.bpf.c:350:15: error: invalid application of 'sizeof' to an incomplete type 'struct timespec64'
>     350 |         __u32 size = sizeof(struct timespec64);
>         |                      ^     ~~~~~~~~~~~~~~~~~~~
>   util/bpf_skel/augmented_raw_syscalls.bpf.c:350:29: note: forward declaration of 'struct timespec64'
>     350 |         __u32 size = sizeof(struct timespec64);
>         |                                    ^
>   2 errors generated.
>   make[2]: *** [Makefile.perf:1158: /tmp/build/perf-tools-next/util/bpf_skel/.tmp/augmented_raw_syscalls.bpf.o] Error 1
>   make[2]: *** Waiting for unfinished jobs....
>   make[1]: *** [Makefile.perf:261: sub-make] Error 2
>   make: *** [Makefile:113: install-bin] Error 2
>   make: Leaving directory '/home/acme/git/perf-tools-next/tools/perf'
>
> So add a Makefile dependency (Namhyung's suggestion) to make sure that
> the new tools/perf/util/bpf_skel/vmlinux/vmlinux.h minimal vmlinux is
> updated in the build directory, providing the moved 'struct timespec64'
> type.
>
> Fixes: 29d16de26df17e94 ("perf augmented_raw_syscalls.bpf: Move 'struct timespec64' to vmlinux.h")
> Cc: Ian Rogers <irogers@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/lkml/CAM9d7ciaj80QZL0AS_T2HNBdMOyS-j1wBHQSYs=U3kHQimY1mQ@xxxxxxxxxxxxxx
> Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/Makefile.perf | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 3cecd51b239707ba..33621114135ee2c8 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -1147,7 +1147,7 @@ ifeq ($(VMLINUX_H),)
>    endif
>  endif
>
> -$(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL)
> +$(SKEL_OUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) $(VMLINUX_H)
>  ifeq ($(VMLINUX_H),)
>         $(QUIET_GEN)$(BPFTOOL) btf dump file $< format c > $@
>  else
> --
> 2.43.0
>