Adding support to attach program in kprobe session mode
with bpf_program__attach_kprobe_multi_opts function.
Adding session bool to bpf_kprobe_multi_opts struct that allows
to load and attach the bpf program via kprobe session.
the attachment to create kprobe multi session.
Also adding new program loader section that allows:
SEC("kprobe.session/bpf_fentry_test*")
and loads/attaches kprobe program as kprobe session.
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/lib/bpf/bpf.c | 1 +
tools/lib/bpf/libbpf.c | 39 +++++++++++++++++++++++++++++++++++++--
tools/lib/bpf/libbpf.h | 4 +++-
3 files changed, 41 insertions(+), 3 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index c9f4e04f38fe..466a29d80124 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -766,6 +766,7 @@ int bpf_link_create(int prog_fd, int target_fd,
return libbpf_err(-EINVAL);
break;
case BPF_TRACE_KPROBE_MULTI:
+ case BPF_TRACE_KPROBE_SESSION:
attr.link_create.kprobe_multi.flags = OPTS_GET(opts, kprobe_multi.flags, 0);
attr.link_create.kprobe_multi.cnt = OPTS_GET(opts, kprobe_multi.cnt, 0);
attr.link_create.kprobe_multi.syms = ptr_to_u64(OPTS_GET(opts, kprobe_multi.syms, 0));
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 898d5d34ecea..16dae279a900 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9273,6 +9273,7 @@ static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_lin
static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
@@ -9289,6 +9290,7 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
+ 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.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
@@ -11381,13 +11383,14 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
struct kprobe_multi_resolve res = {
.pattern = pattern,
};
+ enum bpf_attach_type attach_type;
struct bpf_link *link = NULL;
char errmsg[STRERR_BUFSIZE];
const unsigned long *addrs;
int err, link_fd, prog_fd;
+ bool retprobe, session;
const __u64 *cookies;
const char **syms;
- bool retprobe;
size_t cnt;
if (!OPTS_VALID(opts, bpf_kprobe_multi_opts))
@@ -11426,6 +11429,12 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
}
retprobe = OPTS_GET(opts, retprobe, false);
+ session = OPTS_GET(opts, session, false);
+
+ if (retprobe && session)
+ return libbpf_err_ptr(-EINVAL);
+
+ attach_type = session ? BPF_TRACE_KPROBE_SESSION : BPF_TRACE_KPROBE_MULTI;
lopts.kprobe_multi.syms = syms;
lopts.kprobe_multi.addrs = addrs;
@@ -11440,7 +11449,7 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
}
link->detach = &bpf_link__detach_fd;
- link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_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: %s\n",
@@ -11546,6 +11555,32 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru
return libbpf_get_error(*link);
}
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie,
+ struct bpf_link **link)
+{
+ LIBBPF_OPTS(bpf_kprobe_multi_opts, opts, .session = true);
+ const char *spec;
+ char *pattern;
+ int n;
+
+ *link = NULL;
+
+ /* no auto-attach for SEC("kprobe.session") */
+ if (strcmp(prog->sec_name, "kprobe.session") == 0)
+ return 0;
+
+ spec = prog->sec_name + sizeof("kprobe.session/") - 1;
+ n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
+ if (n < 1) {
+ pr_warn("kprobe session pattern is invalid: %s\n", pattern);
+ return -EINVAL;
+ }
+
+ *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts);
+ free(pattern);
+ return *link ? 0 : -errno;
+}
+
static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
{
char *probe_type = NULL, *binary_path = NULL, *func_name = NULL;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 1333ae20ebe6..c3f77d9260fe 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -539,10 +539,12 @@ struct bpf_kprobe_multi_opts {
size_t cnt;
/* create return kprobes */
bool retprobe;
+ /* create session kprobes */
+ bool session;
size_t :0;
};
-#define bpf_kprobe_multi_opts__last_field retprobe
+#define bpf_kprobe_multi_opts__last_field session
LIBBPF_API struct bpf_link *
bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
--
2.44.0
