On Wed, Dec 17, 2025 at 1:55 AM Menglong Dong <menglong8.dong@gmail.com> wrote:
>
> Add BPF_TRACE_SESSION to libbpf and bpftool.
>
> Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
> ---
> tools/bpf/bpftool/common.c | 1 +
> tools/lib/bpf/bpf.c | 2 ++
> tools/lib/bpf/libbpf.c | 3 +++
> 3 files changed, 6 insertions(+)
>
> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> index e8daf963ecef..534be6cfa2be 100644
> --- a/tools/bpf/bpftool/common.c
> +++ b/tools/bpf/bpftool/common.c
> @@ -1191,6 +1191,7 @@ const char *bpf_attach_type_input_str(enum bpf_attach_type t)
> case BPF_TRACE_FENTRY: return "fentry";
> case BPF_TRACE_FEXIT: return "fexit";
> case BPF_MODIFY_RETURN: return "mod_ret";
> + case BPF_TRACE_SESSION: return "fsession";
> case BPF_SK_REUSEPORT_SELECT: return "sk_skb_reuseport_select";
> case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE: return "sk_skb_reuseport_select_or_migrate";
> default: return libbpf_bpf_attach_type_str(t);
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 21b57a629916..5042df4a5df7 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -794,6 +794,7 @@ int bpf_link_create(int prog_fd, int target_fd,
> case BPF_TRACE_FENTRY:
> case BPF_TRACE_FEXIT:
> case BPF_MODIFY_RETURN:
> + case BPF_TRACE_SESSION:
> case BPF_LSM_MAC:
> attr.link_create.tracing.cookie = OPTS_GET(opts, tracing.cookie, 0);
> if (!OPTS_ZEROED(opts, tracing))
> @@ -917,6 +918,7 @@ int bpf_link_create(int prog_fd, int target_fd,
> case BPF_TRACE_FENTRY:
> case BPF_TRACE_FEXIT:
> case BPF_MODIFY_RETURN:
> + case BPF_TRACE_SESSION:
no need, this is a legacy fallback path for programs that were (at
some point for older kernels) attachable only through
BPF_RAW_TRACEPOINT_OPEN. BPF_LINK_CREATE is sufficient, drop this
line.
> return bpf_raw_tracepoint_open(NULL, prog_fd);
> default:
> return libbpf_err(err);
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index c7c79014d46c..0c095195df31 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -115,6 +115,7 @@ static const char * const attach_type_name[] = {
> [BPF_TRACE_FENTRY] = "trace_fentry",
> [BPF_TRACE_FEXIT] = "trace_fexit",
> [BPF_MODIFY_RETURN] = "modify_return",
> + [BPF_TRACE_SESSION] = "trace_session",
let's use fsession terminology consistently
> [BPF_LSM_MAC] = "lsm_mac",
> [BPF_LSM_CGROUP] = "lsm_cgroup",
> [BPF_SK_LOOKUP] = "sk_lookup",
> @@ -9853,6 +9854,8 @@ static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("fentry.s+", TRACING, BPF_TRACE_FENTRY, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
> SEC_DEF("fmod_ret.s+", TRACING, BPF_MODIFY_RETURN, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
> SEC_DEF("fexit.s+", TRACING, BPF_TRACE_FEXIT, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
> + SEC_DEF("fsession+", TRACING, BPF_TRACE_SESSION, SEC_ATTACH_BTF, attach_trace),
> + SEC_DEF("fsession.s+", TRACING, BPF_TRACE_SESSION, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_trace),
> SEC_DEF("freplace+", EXT, 0, SEC_ATTACH_BTF, attach_trace),
> SEC_DEF("lsm+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF, attach_lsm),
> SEC_DEF("lsm.s+", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm),
> --
> 2.52.0
>