On Mon, Nov 29, 2021 at 2:01 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> When compiling libbpf with gcc 4.8.5, we see:
>
> CC staticobjs/btf_dump.o
> btf_dump.c: In function ‘btf_dump_dump_type_data.isra.24’:
> btf_dump.c:2296:5: error: ‘err’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> if (err < 0)
> ^
> cc1: all warnings being treated as errors
> make: *** [staticobjs/btf_dump.o] Error 1
>
> While gcc 4.8.5 is too old to build the upstream kernel, it's possible it
> could be used to build standalone libbpf which suffers from the same problem.
> Silence the error by initializing 'err' to 0. The warning/error seems to be
> a false positive since err is set early in the function. Regardless we
> shouldn't prevent libbpf from building for this.
>
> Fixes: 920d16af9b42 ("libbpf: BTF dumper support for typed data")
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
Arnaldo also complained about this.
Applied to bpf-next, I don't think it needs to be in the bpf tree. Thanks.
> tools/lib/bpf/btf_dump.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
> index 17db62b..5cae716 100644
> --- a/tools/lib/bpf/btf_dump.c
> +++ b/tools/lib/bpf/btf_dump.c
> @@ -2194,7 +2194,7 @@ static int btf_dump_dump_type_data(struct btf_dump *d,
> __u8 bits_offset,
> __u8 bit_sz)
> {
> - int size, err;
> + int size, err = 0;
>
> size = btf_dump_type_data_check_overflow(d, t, id, data, bits_offset);
> if (size < 0)
> --
> 1.8.3.1
>
