On Fri, Nov 8, 2024 at 5:47 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding support to attach program in uprobe session mode
> with bpf_program__attach_uprobe_multi function.
>
> Adding session bool to bpf_uprobe_multi_opts struct that allows
> to load and attach the bpf program via uprobe session.
> the attachment to create uprobe multi session.
>
> Also adding new program loader section that allows:
> SEC("uprobe.session/bpf_fentry_test*")
>
> and loads/attaches uprobe program as uprobe session.
>
> Adding sleepable hook (uprobe.session.s) as well.
>
> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/lib/bpf/bpf.c | 1 +
> tools/lib/bpf/libbpf.c | 18 ++++++++++++++++--
> tools/lib/bpf/libbpf.h | 4 +++-
> 3 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index 2a4c71501a17..becdfa701c75 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -776,6 +776,7 @@ int bpf_link_create(int prog_fd, int target_fd,
> return libbpf_err(-EINVAL);
> break;
> case BPF_TRACE_UPROBE_MULTI:
> + case BPF_TRACE_UPROBE_SESSION:
> attr.link_create.uprobe_multi.flags = OPTS_GET(opts, uprobe_multi.flags, 0);
> attr.link_create.uprobe_multi.cnt = OPTS_GET(opts, uprobe_multi.cnt, 0);
> attr.link_create.uprobe_multi.path = ptr_to_u64(OPTS_GET(opts, uprobe_multi.path, 0));
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index faac1c79840d..a2bc5bea7ea3 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -9442,8 +9442,10 @@ static const struct bpf_sec_def section_defs[] = {
> SEC_DEF("kprobe.session+", KPROBE, BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
> SEC_DEF("uprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> SEC_DEF("uretprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
> + SEC_DEF("uprobe.session+", KPROBE, BPF_TRACE_UPROBE_SESSION, SEC_NONE, attach_uprobe_multi),
> SEC_DEF("uprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
> SEC_DEF("uretprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
> + SEC_DEF("uprobe.session.s+", KPROBE, BPF_TRACE_UPROBE_SESSION, SEC_SLEEPABLE, attach_uprobe_multi),
> SEC_DEF("ksyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
> SEC_DEF("kretsyscall+", KPROBE, 0, SEC_NONE, attach_ksyscall),
> SEC_DEF("usdt+", KPROBE, 0, SEC_USDT, attach_usdt),
> @@ -11765,7 +11767,9 @@ static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, stru
> ret = 0;
> break;
> case 3:
> + opts.session = str_has_pfx(probe_type, "uprobe.session");
> opts.retprobe = str_has_pfx(probe_type, "uretprobe.multi");
> +
> *link = bpf_program__attach_uprobe_multi(prog, -1, binary_path, func_name, &opts);
> ret = libbpf_get_error(*link);
> break;
> @@ -12014,10 +12018,12 @@ bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
> const unsigned long *ref_ctr_offsets = NULL, *offsets = NULL;
> LIBBPF_OPTS(bpf_link_create_opts, lopts);
> unsigned long *resolved_offsets = NULL;
> + enum bpf_attach_type attach_type;
> int err = 0, link_fd, prog_fd;
> struct bpf_link *link = NULL;
> char errmsg[STRERR_BUFSIZE];
> char full_path[PATH_MAX];
> + bool retprobe, session;
> const __u64 *cookies;
> const char **syms;
> size_t cnt;
> @@ -12088,12 +12094,20 @@ bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
> offsets = resolved_offsets;
> }
>
> + retprobe = OPTS_GET(opts, retprobe, false);
> + session = OPTS_GET(opts, session, false);
> +
> + if (retprobe && session)
> + return libbpf_err_ptr(-EINVAL);
Hey Jiri,
Coverity says that we are leaking offsets (resolved_offsets) here.
Please send a fix, thanks.
> +
> + attach_type = session ? BPF_TRACE_UPROBE_SESSION : BPF_TRACE_UPROBE_MULTI;
> +
> lopts.uprobe_multi.path = path;
> lopts.uprobe_multi.offsets = offsets;
> lopts.uprobe_multi.ref_ctr_offsets = ref_ctr_offsets;
> lopts.uprobe_multi.cookies = cookies;
> lopts.uprobe_multi.cnt = cnt;
> - lopts.uprobe_multi.flags = OPTS_GET(opts, retprobe, false) ? BPF_F_UPROBE_MULTI_RETURN : 0;
> + lopts.uprobe_multi.flags = retprobe ? BPF_F_UPROBE_MULTI_RETURN : 0;
>
> if (pid == 0)
> pid = getpid();
> @@ -12107,7 +12121,7 @@ bpf_program__attach_uprobe_multi(const struct bpf_program *prog,
> }
> link->detach = &bpf_link__detach_fd;
>
> - link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_UPROBE_MULTI, &lopts);
> + link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
> if (link_fd < 0) {
> err = -errno;
> pr_warn("prog '%s': failed to attach multi-uprobe: %s\n",
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 91484303849c..b2ce3a72b11d 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -577,10 +577,12 @@ struct bpf_uprobe_multi_opts {
> size_t cnt;
> /* create return uprobes */
> bool retprobe;
> + /* create session kprobes */
> + bool session;
> size_t :0;
> };
>
> -#define bpf_uprobe_multi_opts__last_field retprobe
> +#define bpf_uprobe_multi_opts__last_field session
>
> /**
> * @brief **bpf_program__attach_uprobe_multi()** attaches a BPF program
> --
> 2.47.0
>
