Dynamic tracepoints can be created using debugfs. For example:
echo 'p:myprobe kernel_clone args' >> /sys/kernel/debug/tracing/kprobe_events
This command creates a new tracepoint under debugfs:
$ ls /sys/kernel/debug/tracing/events/kprobes/myprobe/
enable filter format hist id trigger
Although this dynamic tracepoint appears as a tracepoint, it is internally
implemented as a kprobe. However, it must be attached as a tracepoint to
function correctly in certain contexts.
This update adds support in libbpf for handling such tracepoints,
simplifying their usage and integration in BPF workflows.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
tools/lib/bpf/libbpf.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 66173ddb5a2d..077bec761ebf 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9504,6 +9504,7 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("struct_ops.s+", STRUCT_OPS, 0, SEC_SLEEPABLE),
SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE),
SEC_DEF("netfilter", NETFILTER, BPF_NETFILTER, SEC_NONE),
+ SEC_DEF("dynamic_tp+", KPROBE, 0, SEC_NONE, attach_tp),
};
int libbpf_register_prog_handler(const char *sec,
@@ -12500,6 +12501,8 @@ static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_lin
/* extract "tp/<category>/<name>" or "tracepoint/<category>/<name>" */
if (str_has_pfx(prog->sec_name, "tp/"))
tp_cat = sec_name + sizeof("tp/") - 1;
+ else if (str_has_pfx(prog->sec_name, "dynamic_tp/"))
+ tp_cat = sec_name + sizeof("dynamic_tp/") - 1;
else
tp_cat = sec_name + sizeof("tracepoint/") - 1;
tp_name = strchr(tp_cat, '/');
--
2.43.5
