Re: [PATCH v2 bpf-next] selftests/bpf: Add -Wuninitialized flag to bpf prog flags

[Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>]

On Thu, Mar 2, 2023 at 3:35 PM Dave Marchevsky <davemarchevsky@xxxxxx> wrote:
>
> diff --git a/tools/testing/selftests/bpf/progs/rbtree_fail.c b/tools/testing/selftests/bpf/progs/rbtree_fail.c
> index bf3cba115897..4614cd7bfa46 100644
> --- a/tools/testing/selftests/bpf/progs/rbtree_fail.c
> +++ b/tools/testing/selftests/bpf/progs/rbtree_fail.c
> @@ -232,8 +232,9 @@ long rbtree_api_first_release_unlock_escape(void *ctx)
>
>         bpf_spin_lock(&glock);
>         res = bpf_rbtree_first(&groot);
> -       if (res)
> -               n = container_of(res, struct node_data, node);
> +       if (!res)
> +               return 1;
> +       n = container_of(res, struct node_data, node);
>         bpf_spin_unlock(&glock);

It has the same issue.
I don't think we should rely on the order of basic blocks.
If 'return 1' block is happened to be a fallthrough
the verifier will error on 'lock is still held'.