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libbpf: Add uprobe multi link support to bpf_program__attach_usdt

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Adding support for usdt_manager_attach_usdt to use uprobe_multi
link to attach to usdt probes.

The uprobe_multi support is detected before the usdt program is
loaded and its expected_attach_type is set accordingly.

If uprobe_multi support is detected the usdt_manager_attach_usdt
gathers uprobes info and calls bpf_program__attach_uprobe to
create all needed uprobes.

If uprobe_multi support is not detected the old behaviour stays.

Also adding usdt.s program section for sleepable usdt probes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230809083440.3209381-18-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jiri Olsa
2023-08-09 10:34:29 +02:00
committed by Andrii Nakryiko
parent 60cf42249b
commit 74188c1740
2 changed files with 82 additions and 17 deletions
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13
src/libbpf.c
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@@ -367,6 +367,8 @@ enum sec_def_flags {
SEC_SLEEPABLE = 8,
/* BPF program support non-linear XDP buffer */
SEC_XDP_FRAGS = 16,
/* Setup proper attach type for usdt probes. */
SEC_USDT = 32,
};
struct bpf_sec_def {
@@ -6828,6 +6830,10 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog,
if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_FRAGS))
opts->prog_flags |= BPF_F_XDP_HAS_FRAGS;
/* special check for usdt to use uprobe_multi link */
if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK))
prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI;
if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) {
int btf_obj_fd = 0, btf_type_id = 0, err;
const char *attach_name;
@@ -6896,7 +6902,6 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
if (!insns || !insns_cnt)
return -EINVAL;
load_attr.expected_attach_type = prog->expected_attach_type;
if (kernel_supports(obj, FEAT_PROG_NAME))
prog_name = prog->name;
load_attr.attach_prog_fd = prog->attach_prog_fd;
@@ -6932,6 +6937,9 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
insns_cnt = prog->insns_cnt;
}
/* allow prog_prepare_load_fn to change expected_attach_type */
load_attr.expected_attach_type = prog->expected_attach_type;
if (obj->gen_loader) {
bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name,
license, insns, insns_cnt, &load_attr,
@@ -8759,7 +8767,8 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("uretprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, 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_NONE, attach_usdt),
SEC_DEF("usdt+", KPROBE, 0, SEC_USDT, attach_usdt),
SEC_DEF("usdt.s+", KPROBE, 0, SEC_USDT | SEC_SLEEPABLE, attach_usdt),
SEC_DEF("tc/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), /* alias for tcx */
SEC_DEF("tc/egress", SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE), /* alias for tcx */
SEC_DEF("tcx/ingress", SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE),