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Date: Mon, 25 Jul 2022 06:23:34 +0000
From: Jianlin Lv <iecedge@...il.com>
To: corbet@....net, rostedt@...dmis.org, mingo@...hat.com
Cc: iecedge@...il.com, jianlv@...y.com, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org
Subject: [PATCH v2] tracing/kprobes: Add method to display private kprobes in tracefs
The private kprobes are not added to the global list dyn_event_list,
so there is a missing interface to show probe hit and probe miss.
This patch adds a profiling interface to check the number of hits or
misses for private kprobes.
Signed-off-by: Jianlin Lv <iecedge@...il.com>
---
v2: update commit message
---
Documentation/trace/kprobetrace.rst | 6 +++-
kernel/trace/trace_dynevent.c | 20 +++++++++++
kernel/trace/trace_dynevent.h | 37 ++++++++++++++++++++
kernel/trace/trace_kprobe.c | 54 +++++++++++++++++++++++++++++
4 files changed, 116 insertions(+), 1 deletion(-)
diff --git a/Documentation/trace/kprobetrace.rst b/Documentation/trace/kprobetrace.rst
index b175d88f31eb..8815d64dd8a6 100644
--- a/Documentation/trace/kprobetrace.rst
+++ b/Documentation/trace/kprobetrace.rst
@@ -146,7 +146,11 @@ trigger:
Event Profiling
---------------
You can check the total number of probe hits and probe miss-hits via
-/sys/kernel/debug/tracing/kprobe_profile.
+/sys/kernel/debug/tracing/kprobe_profile or
+/sys/kernel/debug/tracing/kprobe_local_profile.
+All kprobe events created by kprobe_events will be added to the global
+list, you can get their profiling via kprobe_profile; kprobe_local_profile
+shows profiling for private kprobe events created by perf_kprobe pmu.
The first column is event name, the second is the number of probe hits,
the third is the number of probe miss-hits.
diff --git a/kernel/trace/trace_dynevent.c b/kernel/trace/trace_dynevent.c
index 076b447a1b88..70ec99cd9c53 100644
--- a/kernel/trace/trace_dynevent.c
+++ b/kernel/trace/trace_dynevent.c
@@ -181,6 +181,26 @@ static const struct seq_operations dyn_event_seq_op = {
.show = dyn_event_seq_show
};
+#ifdef CONFIG_KPROBE_EVENTS
+LIST_HEAD(local_event_list);
+
+void *local_event_seq_start(struct seq_file *m, loff_t *pos)
+{
+ mutex_lock(&event_mutex);
+ return seq_list_start(&local_event_list, *pos);
+}
+
+void *local_event_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ return seq_list_next(v, &local_event_list, pos);
+}
+
+void local_event_seq_stop(struct seq_file *m, void *v)
+{
+ mutex_unlock(&event_mutex);
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
/*
* dyn_events_release_all - Release all specific events
* @type: the dyn_event_operations * which filters releasing events
diff --git a/kernel/trace/trace_dynevent.h b/kernel/trace/trace_dynevent.h
index 936477a111d3..e30193470295 100644
--- a/kernel/trace/trace_dynevent.h
+++ b/kernel/trace/trace_dynevent.h
@@ -101,6 +101,43 @@ void dyn_event_seq_stop(struct seq_file *m, void *v);
int dyn_events_release_all(struct dyn_event_operations *type);
int dyn_event_release(const char *raw_command, struct dyn_event_operations *type);
+#ifdef CONFIG_KPROBE_EVENTS
+extern struct list_head local_event_list;
+
+static inline
+int local_event_init(struct dyn_event *ev, struct dyn_event_operations *ops)
+{
+ if (!ev || !ops)
+ return -EINVAL;
+
+ INIT_LIST_HEAD(&ev->list);
+ ev->ops = ops;
+ return 0;
+}
+
+static inline int local_event_add(struct dyn_event *ev)
+{
+ lockdep_assert_held(&event_mutex);
+
+ if (!ev || !ev->ops)
+ return -EINVAL;
+
+ list_add_tail(&ev->list, &local_event_list);
+ return 0;
+}
+
+static inline void local_event_remove(struct dyn_event *ev)
+{
+ lockdep_assert_held(&event_mutex);
+ list_del_init(&ev->list);
+}
+
+void *local_event_seq_start(struct seq_file *m, loff_t *pos);
+void *local_event_seq_next(struct seq_file *m, void *v, loff_t *pos);
+void local_event_seq_stop(struct seq_file *m, void *v);
+
+#endif /* CONFIG_KPROBE_EVENTS */
+
/*
* for_each_dyn_event - iterate over the dyn_event list
* @pos: the struct dyn_event * to use as a loop cursor
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a245ea673715..76f500b17b46 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1213,6 +1213,52 @@ static const struct file_operations kprobe_profile_ops = {
.release = seq_release,
};
+#ifdef CONFIG_KPROBE_EVENTS
+/* kprobe Local profile */
+static int local_probes_profile_seq_show(struct seq_file *m, void *v)
+{
+ struct dyn_event *ev = v;
+ struct trace_kprobe *tk;
+
+ if (!is_trace_kprobe(ev))
+ return 0;
+
+ tk = to_trace_kprobe(ev);
+ seq_printf(m, " %-44s %15lu %15lu\n",
+ trace_probe_name(&tk->tp),
+ trace_kprobe_nhit(tk),
+ tk->rp.kp.nmissed);
+
+ return 0;
+}
+
+static const struct seq_operations local_profile_seq_op = {
+ .start = local_event_seq_start,
+ .next = local_event_seq_next,
+ .stop = local_event_seq_stop,
+ .show = local_probes_profile_seq_show
+};
+
+static int local_profile_open(struct inode *inode, struct file *file)
+{
+ int ret;
+
+ ret = security_locked_down(LOCKDOWN_TRACEFS);
+ if (ret)
+ return ret;
+
+ return seq_open(file, &local_profile_seq_op);
+}
+
+static const struct file_operations kprobe_local_profile_ops = {
+ .owner = THIS_MODULE,
+ .open = local_profile_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+#endif /* CONFIG_KPROBE_EVENTS */
+
/* Kprobe specific fetch functions */
/* Return the length of string -- including null terminal byte */
@@ -1830,6 +1876,7 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
if (ret < 0)
goto error;
+ local_event_add(&tk->devent);
return trace_probe_event_call(&tk->tp);
error:
free_trace_kprobe(tk);
@@ -1849,6 +1896,7 @@ void destroy_local_trace_kprobe(struct trace_event_call *event_call)
return;
}
+ local_event_remove(&tk->devent);
__unregister_trace_kprobe(tk);
free_trace_kprobe(tk);
@@ -1929,6 +1977,12 @@ static __init int init_kprobe_trace(void)
trace_create_file("kprobe_profile", TRACE_MODE_READ,
NULL, NULL, &kprobe_profile_ops);
+#ifdef CONFIG_KPROBE_EVENTS
+ /* kprobe Local profile */
+ tracefs_create_file("kprobe_local_profile", TRACE_MODE_READ,
+ NULL, NULL, &kprobe_local_profile_ops);
+#endif /* CONFIG_KPROBE_EVENTS */
+
setup_boot_kprobe_events();
return 0;
--
2.25.1
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