From: "Steven Rostedt (Red Hat)" <[email protected]>
Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance
directories to let users filter of functions to trace for the given instance.
Signed-off-by: Steven Rostedt <[email protected]>
---
include/linux/ftrace.h | 2 ++
kernel/trace/ftrace.c | 39 ++++++++++++++++++++++++++++++++++-----
kernel/trace/trace.c | 4 ++++
kernel/trace/trace.h | 25 ++++++++++++++++++++++++-
kernel/trace/trace_functions.c | 40 ++++++++++++++++++++++++++++++++--------
5 files changed, 96 insertions(+), 14 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ef1607e..e6141be 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -92,6 +92,7 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
* STUB - The ftrace_ops is just a place holder.
* INITIALIZED - The ftrace_ops has already been initialized (first use time
* register_ftrace_function() is called, it will initialized the ops)
+ * DELETED - The ops are being deleted, do not let them be registered again.
*/
enum {
FTRACE_OPS_FL_ENABLED = 1 << 0,
@@ -103,6 +104,7 @@ enum {
FTRACE_OPS_FL_RECURSION_SAFE = 1 << 6,
FTRACE_OPS_FL_STUB = 1 << 7,
FTRACE_OPS_FL_INITIALIZED = 1 << 8,
+ FTRACE_OPS_FL_DELETED = 1 << 9,
};
/*
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2b3e239..dcee546 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -436,6 +436,9 @@ static int remove_ftrace_list_ops(struct ftrace_ops **list,
static int __register_ftrace_function(struct ftrace_ops *ops)
{
+ if (ops->flags & FTRACE_OPS_FL_DELETED)
+ return -EINVAL;
+
if (FTRACE_WARN_ON(ops == &global_ops))
return -EINVAL;
@@ -4112,6 +4115,36 @@ static const struct file_operations ftrace_graph_notrace_fops = {
};
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+void ftrace_create_filter_files(struct ftrace_ops *ops,
+ struct dentry *parent)
+{
+
+ trace_create_file("set_ftrace_filter", 0644, parent,
+ ops, &ftrace_filter_fops);
+
+ trace_create_file("set_ftrace_notrace", 0644, parent,
+ ops, &ftrace_notrace_fops);
+}
+
+/*
+ * The name "destroy_filter_files" is really a misnomer. Although
+ * in the future, it may actualy delete the files, but this is
+ * really intended to make sure the ops passed in are disabled
+ * and that when this function returns, the caller is free to
+ * free the ops.
+ *
+ * The "destroy" name is only to match the "create" name that this
+ * should be paired with.
+ */
+void ftrace_destroy_filter_files(struct ftrace_ops *ops)
+{
+ mutex_lock(&ftrace_lock);
+ if (ops->flags & FTRACE_OPS_FL_ENABLED)
+ ftrace_shutdown(ops, 0);
+ ops->flags |= FTRACE_OPS_FL_DELETED;
+ mutex_unlock(&ftrace_lock);
+}
+
static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
{
@@ -4121,11 +4154,7 @@ static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
trace_create_file("enabled_functions", 0444,
d_tracer, NULL, &ftrace_enabled_fops);
- trace_create_file("set_ftrace_filter", 0644, d_tracer,
- &global_ops, &ftrace_filter_fops);
-
- trace_create_file("set_ftrace_notrace", 0644, d_tracer,
- &global_ops, &ftrace_notrace_fops);
+ ftrace_create_filter_files(&global_ops, d_tracer);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
trace_create_file("set_graph_function", 0444, d_tracer,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f9f22c4..d95ec28 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6161,6 +6161,7 @@ static int instance_delete(const char *name)
tracing_set_nop(tr);
event_trace_del_tracer(tr);
+ ftrace_destroy_function_files(tr);
debugfs_remove_recursive(tr->dir);
free_percpu(tr->trace_buffer.data);
ring_buffer_free(tr->trace_buffer.buffer);
@@ -6291,6 +6292,9 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
trace_create_file("tracing_on", 0644, d_tracer,
tr, &rb_simple_fops);
+ if (ftrace_create_function_files(tr, d_tracer))
+ WARN(1, "Could not allocate function filter files");
+
#ifdef CONFIG_TRACER_SNAPSHOT
trace_create_file("snapshot", 0644, d_tracer,
tr, &snapshot_fops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 35cca05..ffc314b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -819,13 +819,36 @@ static inline int ftrace_trace_task(struct task_struct *task)
return test_tsk_trace_trace(task);
}
extern int ftrace_is_dead(void);
+int ftrace_create_function_files(struct trace_array *tr,
+ struct dentry *parent);
+void ftrace_destroy_function_files(struct trace_array *tr);
#else
static inline int ftrace_trace_task(struct task_struct *task)
{
return 1;
}
static inline int ftrace_is_dead(void) { return 0; }
-#endif
+static inline int
+ftrace_create_function_files(struct trace_array *tr,
+ struct dentry *parent)
+{
+ return 0;
+}
+static inline void ftrace_destroy_function_files(struct trace_array *tr) { }
+#endif /* CONFIG_FUNCTION_TRACER */
+
+#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_DYNAMIC_FTRACE)
+void ftrace_create_filter_files(struct ftrace_ops *ops,
+ struct dentry *parent);
+void ftrace_destroy_filter_files(struct ftrace_ops *ops);
+#else
+/*
+ * The ops parameter passed in is usually undefined.
+ * This must be a macro.
+ */
+#define ftrace_create_filter_files(ops, parent) do { } while (0)
+#define ftrace_destroy_filter_files(ops) do { } while (0)
+#endif /* CONFIG_FUNCTION_TRACER && CONFIG_DYNAMIC_FTRACE */
int ftrace_event_is_function(struct ftrace_event_call *call);
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 3f8dc1c..5b781d2 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -52,10 +52,34 @@ static int allocate_ftrace_ops(struct trace_array *tr)
return 0;
}
+
+int ftrace_create_function_files(struct trace_array *tr,
+ struct dentry *parent)
+{
+ int ret;
+
+ /* The top level array uses the "global_ops". */
+ if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL)) {
+ ret = allocate_ftrace_ops(tr);
+ if (ret)
+ return ret;
+ }
+
+ ftrace_create_filter_files(tr->ops, parent);
+
+ return 0;
+}
+
+void ftrace_destroy_function_files(struct trace_array *tr)
+{
+ ftrace_destroy_filter_files(tr->ops);
+ kfree(tr->ops);
+ tr->ops = NULL;
+}
+
static int function_trace_init(struct trace_array *tr)
{
struct ftrace_ops *ops;
- int ret;
if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
/* There's only one global tr */
@@ -69,10 +93,13 @@ static int function_trace_init(struct trace_array *tr)
else
ops = &trace_ops;
tr->ops = ops;
- } else {
- ret = allocate_ftrace_ops(tr);
- if (ret)
- return ret;
+ } else if (!tr->ops) {
+ /*
+ * Instance trace_arrays get their ops allocated
+ * at instance creation. Unless it failed
+ * the allocation.
+ */
+ return -ENOMEM;
}
tr->trace_buffer.cpu = get_cpu();
@@ -87,9 +114,6 @@ static void function_trace_reset(struct trace_array *tr)
{
tracing_stop_function_trace(tr);
tracing_stop_cmdline_record();
- if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
- kfree(tr->ops);
- tr->ops = NULL;
}
static void function_trace_start(struct trace_array *tr)
--
1.8.5.3