[PATCH 1/3] kobject: add kobject trace points

[Shuah Khan]

Add kobject trace points to track kobject operations: init, add, set_name,
init_and_add, create_and_add, move, rename, get, put, cleanup, and del.

Kobject trace points can aid in debugging, generating status and graphs
on kobjects in the kernel and their hierarchy.

Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
---
 include/trace/events/kobject.h | 259 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 259 insertions(+)
 create mode 100644 include/trace/events/kobject.h

diff --git a/include/trace/events/kobject.h b/include/trace/events/kobject.h
new file mode 100644
index 0000000..6a29665
--- /dev/null
+++ b/include/trace/events/kobject.h
@@ -0,0 +1,259 @@
+/*
+ * kobject trace points
+ *
+ * Copyright (C) 2016 Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
+ *
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM kobject
+
+#if !defined(_TRACE_KOBJECT_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_KOBJECT_H
+
+#include <linux/tracepoint.h>
+#include <linux/kobject.h>
+
+/* kobject_init_class */
+DECLARE_EVENT_CLASS(kobject_init_class,
+
+	TP_PROTO(struct kobject *kobj),
+
+	TP_ARGS(kobj),
+
+	TP_STRUCT__entry(
+		__field(void *, kobj)
+		__field(int, state_initialized)
+	),
+
+	TP_fast_assign(
+		__entry->kobj = kobj;
+		__entry->state_initialized = kobj->state_initialized;
+	),
+
+	TP_printk("KOBJECT: %p state=%d",
+		  __entry->kobj,
+		  __entry->state_initialized
+	));
+
+/**
+ * kobject_init	- called from kobject_init() when kobject is initialized
+ * @kobj:	- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_init_class, kobject_init,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/* kobject_class */
+DECLARE_EVENT_CLASS(kobject_class,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj),
+
+	TP_STRUCT__entry(
+		__field(void *, kobj)
+		__string(name, kobject_name(kobj))
+		__field(int, state_initialized)
+		__field(void *, parent)
+		__string(pname, kobj->parent ? kobject_name(kobj->parent) : "")
+		__field(int, count)
+	),
+
+	TP_fast_assign(
+		__entry->kobj = kobj;
+		__assign_str(name, kobject_name(kobj));
+		__entry->state_initialized = kobj->state_initialized;
+		__entry->parent = kobj->parent;
+		__assign_str(pname,
+			     kobj->parent ? kobject_name(kobj->parent) : "");
+		__entry->count = atomic_read(&kobj->kref.refcount);
+	),
+
+	TP_printk("KOBJECT: %s (%p) state=%d parent= %s (%p) counter= %d",
+		  __get_str(name),
+		  __entry->kobj,
+		  __entry->state_initialized,
+		  __get_str(pname),
+		  __entry->parent,
+		  __entry->count
+	));
+
+/**
+ * kobject_add	- called from kobject_add() when kobject is added
+ * @kobj:	- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_add,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_init_and_add	- called from kobject_init_and_add()
+ * @kobj:		- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_init_and_add,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_create_and_add	- called from kobject_create_and_add()
+ * @kobj:			- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_create_and_add,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_set_name	- called from kobject_set_name()
+ * @kobj:		- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_set_name,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_del	- called from kobject_del()
+ * @kobj:	- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_del,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_cleanup	- called from kobject_cleanup()
+ * @kobj:		- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_cleanup,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+/**
+ * kobject_get	- called from kobject_get()
+ * @kobj:	- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_class, kobject_get,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj));
+
+/**
+ * kobject_put	- called from kobject_put()
+ * @kobj:	- pointer to struct kobject
+ *
+ * Trace is called before kref_put() to avoid use-after-free on kobj, in case
+ * kobject is released. Decrement the counter before printing the value.
+ */
+TRACE_EVENT(kobject_put,
+
+	TP_PROTO(struct kobject *kobj),
+	TP_ARGS(kobj),
+
+	TP_STRUCT__entry(
+		__field(void *, kobj)
+		__string(name, kobject_name(kobj))
+		__field(int, state_initialized)
+		__field(void *, parent)
+		__string(pname, kobj->parent ? kobject_name(kobj->parent) : "")
+		__field(int, count)
+	),
+
+	TP_fast_assign(
+		__entry->kobj = kobj;
+		__assign_str(name, kobject_name(kobj));
+		__entry->state_initialized = kobj->state_initialized;
+		__entry->parent = kobj->parent;
+		__assign_str(pname,
+			     kobj->parent ? kobject_name(kobj->parent) : "");
+		__entry->count = atomic_read(&kobj->kref.refcount) - 1;
+	),
+
+	TP_printk("KOBJECT: %s (%p) state=%d parent= %s (%p) counter= %d",
+		  __get_str(name),
+		  __entry->kobj,
+		  __entry->state_initialized,
+		  __get_str(pname),
+		  __entry->parent,
+		  __entry->count
+	));
+
+/* kobject_move_class */
+DECLARE_EVENT_CLASS(kobject_move_class,
+
+	TP_PROTO(struct kobject *kobj, struct kobject *old_parent),
+	TP_ARGS(kobj, old_parent),
+
+	TP_STRUCT__entry(
+		__field(void *, kobj)
+		__string(name, kobject_name(kobj))
+		__field(int, state_initialized)
+		__field(void *, parent)
+		__string(pname, kobj->parent ? kobject_name(kobj->parent) : "")
+	),
+
+	TP_fast_assign(
+		__entry->kobj = kobj;
+		__assign_str(name, kobject_name(kobj));
+		__entry->state_initialized = kobj->state_initialized;
+		__entry->parent = kobj->parent;
+		__assign_str(pname,
+			     kobj->parent ? kobject_name(kobj->parent) : "");
+	),
+
+	TP_printk("KOBJECT: %s (%p) state=%d parent= %s (%p)",
+		  __get_str(name),
+		  __entry->kobj,
+		  __entry->state_initialized,
+		  __get_str(pname),
+		  __entry->parent
+	));
+
+/**
+ * kobject_move	- called from kobject_move()
+ * @kobj:	- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_move_class, kobject_move,
+
+	TP_PROTO(struct kobject *kobj, struct kobject *old_parent),
+	TP_ARGS(kobj, old_parent));
+
+/* kobject_rename_class */
+DECLARE_EVENT_CLASS(kobject_rename_class,
+
+	TP_PROTO(struct kobject *kobj, const char *old),
+	TP_ARGS(kobj, old),
+
+	TP_STRUCT__entry(
+		__field(void *, kobj)
+		__string(name, kobject_name(kobj))
+		__string(oldname, old)
+	),
+
+	TP_fast_assign(
+		__entry->kobj = kobj;
+		__assign_str(name, kobject_name(kobj));
+		__assign_str(oldname, old);
+	),
+
+	TP_printk("KOBJECT: %s (%p) oldname= %s",
+		  __get_str(name),
+		  __entry->kobj,
+		  __get_str(oldname)
+	));
+
+/**
+ * kobject_rename	- called from kobject_rename()
+ * @kobj:		- pointer to struct kobject
+ */
+DEFINE_EVENT(kobject_rename_class, kobject_rename,
+
+	TP_PROTO(struct kobject *kobj, const char *old),
+	TP_ARGS(kobj, old));
+
+#endif /* #if !defined(_TRACE_KOBJECT_H) ... */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.7.4