Re: [PATCH bpf-next] bpf: Enforce 'return 0' in BTF-enabled raw_tp programs
From: Andrii Nakryiko <hidden>
Date: 2019-10-29 04:32:45
Also in:
bpf
On 10/28/19 8:24 PM, Alexei Starovoitov wrote:
The return value of raw_tp programs is ignored by __bpf_trace_run() that calls them. The verifier also allows any value to be returned. For BTF-enabled raw_tp lets enforce 'return 0', so that return value can be used for something in the future. Signed-off-by: Alexei Starovoitov <ast@kernel.org> ---
Looks good, if the return value is ignored, no need to specify anything but 0 for now. Acked-by: Andrii Nakryiko <redacted>
quoted hunk ↗ jump to hunk
kernel/bpf/verifier.c | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c59778c0fc4d..6b0de04f8b91 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c@@ -6279,6 +6279,11 @@ static int check_return_code(struct bpf_verifier_env *env) case BPF_PROG_TYPE_CGROUP_SYSCTL: case BPF_PROG_TYPE_CGROUP_SOCKOPT: break; + case BPF_PROG_TYPE_RAW_TRACEPOINT: + if (!env->prog->aux->attach_btf_id) + return 0; + range = tnum_const(0); + break; default: return 0; }