netdev - Re: [PATCH bpf-next] bpf: fix static checker warning

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Message-ID: <bd0bc378-5ff8-dd80-7b07-6c946f3eaedf@iogearbox.net>
Date:   Wed, 27 Nov 2019 01:07:55 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Alexei Starovoitov <ast@...nel.org>, davem@...emloft.net
Cc:     dan.carpenter@...cle.com, netdev@...r.kernel.org,
        bpf@...r.kernel.org, kernel-team@...com
Subject: Re: [PATCH bpf-next] bpf: fix static checker warning

On 11/27/19 12:01 AM, Alexei Starovoitov wrote:
> kernel/bpf/btf.c:4023 btf_distill_func_proto()
>          error: potentially dereferencing uninitialized 't'.
> 
> kernel/bpf/btf.c
>    4012          nargs = btf_type_vlen(func);
>    4013          if (nargs >= MAX_BPF_FUNC_ARGS) {
>    4014                  bpf_log(log,
>    4015                          "The function %s has %d arguments. Too many.\n",
>    4016                          tname, nargs);
>    4017                  return -EINVAL;
>    4018          }
>    4019          ret = __get_type_size(btf, func->type, &t);
>                                                         ^^
> t isn't initialized for the first -EINVAL return
> 
> This is unlikely path, since BTF should have been validated at this point.
> Fix it by returning 'void' BTF.
> 
> Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
> Signed-off-by: Alexei Starovoitov <ast@...nel.org>

Applied, thanks!