diff mbox series

[v2,bpf-next,01/20] bpf: Allow kfuncs return 'void *'

Message ID 20240209040608.98927-2-alexei.starovoitov@gmail.com (mailing list archive)
State New
Headers show
Series bpf: Introduce BPF arena. | expand

Commit Message

Alexei Starovoitov Feb. 9, 2024, 4:05 a.m. UTC 
From: Alexei Starovoitov <ast@kernel.org>

Recognize return of 'void *' from kfunc as returning unknown scalar.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/bpf/verifier.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Kumar Kartikeya Dwivedi Feb. 10, 2024, 6:49 a.m. UTC | #1 
On Fri, 9 Feb 2024 at 05:06, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> From: Alexei Starovoitov <ast@kernel.org>
>
> Recognize return of 'void *' from kfunc as returning unknown scalar.
>
> Acked-by: Andrii Nakryiko <andrii@kernel.org>
> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
> ---

Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

>  kernel/bpf/verifier.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index ddaf09db1175..d9c2dbb3939f 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -12353,6 +12353,9 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
>                                         meta.func_name);
>                                 return -EFAULT;
>                         }
> +               } else if (btf_type_is_void(ptr_type)) {
> +                       /* kfunc returning 'void *' is equivalent to returning scalar */
> +                       mark_reg_unknown(env, regs, BPF_REG_0);
>                 } else if (!__btf_type_is_struct(ptr_type)) {
>                         if (!meta.r0_size) {
>                                 __u32 sz;
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ddaf09db1175..d9c2dbb3939f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12353,6 +12353,9 @@  static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 					meta.func_name);
 				return -EFAULT;
 			}
+		} else if (btf_type_is_void(ptr_type)) {
+			/* kfunc returning 'void *' is equivalent to returning scalar */
+			mark_reg_unknown(env, regs, BPF_REG_0);
 		} else if (!__btf_type_is_struct(ptr_type)) {
 			if (!meta.r0_size) {
 				__u32 sz;