Commit 88d1d4a7 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Martin KaFai Lau
Browse files

bpf: Allow kfuncs return 'void *' 



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

Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20240307031228.42896-2-alexei.starovoitov@gmail.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent e63985ec

kernel/bpf/verifier.c

+3 −0
Original line number Diff line number Diff line
@@ -12364,6 +12364,9 @@ 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;