Re: [PATCH] libbpf: Fix build on read-only filesystems

[Andrii Nakryiko]

On Thu, Dec 19, 2019 at 7:26 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> I got the following error when I tried to build perf on a read-only
> filesystem with O=dir option.
>
>   $ cd /some/where/ro/linux/tools/perf
>   $ make O=$HOME/build/perf
>   ...
>     CC       /home/namhyung/build/perf/lib.o
>   /bin/sh: bpf_helper_defs.h: Read-only file system
>   make[3]: *** [Makefile:184: bpf_helper_defs.h] Error 1
>   make[2]: *** [Makefile.perf:778: /home/namhyung/build/perf/libbpf.a] Error 2
>   make[2]: *** Waiting for unfinished jobs....
>     LD       /home/namhyung/build/perf/libperf-in.o
>     AR       /home/namhyung/build/perf/libperf.a
>     PERF_VERSION = 5.4.0
>   make[1]: *** [Makefile.perf:225: sub-make] Error 2
>   make: *** [Makefile:70: all] Error 2
>
> It was becaused bpf_helper_defs.h was generated in current directory.
> Move it to OUTPUT directory.
>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> ---

Overall nothing is obviously broken, except you need to fix up
selftests/bpf's Makefile as well.

BTW, this patch doesn't apply cleanly to latest bpf-next, so please rebase.

Also subject prefix should look like [PATCH bpf-next] if it's meant to
be applied against bpf-next.

>  tools/lib/bpf/Makefile | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>

[...]