Re: [PATCH bpf-next v4 01/11] bpf: Save PTR_TO_BTF_ID register state when spilling to stack

[Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx>]

On January 8, 2020 9:44:24 PM GMT-03:00, Martin KaFai Lau <kafai@xxxxxx> wrote:
>This patch makes the verifier save the PTR_TO_BTF_ID register state
>when
>spilling to the stack.

You say what it does, but not why that is needed :-/

- Arnaldo
>
>Acked-by: Yonghong Song <yhs@xxxxxx>
>Signed-off-by: Martin KaFai Lau <kafai@xxxxxx>
>---
> kernel/bpf/verifier.c | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
>index 6f63ae7a370c..d433d70022fd 100644
>--- a/kernel/bpf/verifier.c
>+++ b/kernel/bpf/verifier.c
>@@ -1916,6 +1916,7 @@ static bool is_spillable_regtype(enum
>bpf_reg_type type)
> 	case PTR_TO_TCP_SOCK:
> 	case PTR_TO_TCP_SOCK_OR_NULL:
> 	case PTR_TO_XDP_SOCK:
>+	case PTR_TO_BTF_ID:
> 		return true;
> 	default:
> 		return false;