tracing: A couple of fixes

Linus,

This contains two fixes.

The first is to remove a duplication of creating debugfs files that already exist and causes an error report to be printed due to the failure of the second creation.

The second is a memory leak fix that was introduced in 3.14.

Please pull the latest trace-fixes-v3.15-rc1 tree, which can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-fixes-v3.15-rc1

Tag SHA1: cda50faf0eace20c60940638a550ecd5e9eac4c1 Head SHA1: 6ea6215fe394e320468589d9bba464a48f6d823a

Steven Rostedt (Red Hat) (1):
tracing: Do not try to recreated toplevel set_ftrace_* files

zhangwei(Jovi) (1):
tracing/uprobes: Fix uprobe_cpu_buffer memory leak

----

 kernel/trace/trace_functions.c | 16 ++++++++++------
 kernel/trace/trace_uprobe.c    |  6 ++++++
 2 files changed, 16 insertions(+), 6 deletions(-)

From: "Steven Rostedt (Red Hat)" <[email protected]>

With the restructing of the function tracer working with instances, the "top level" buffer is a bit special, as the function tracing is mapped to the same set of filters. This is done by using a "global_ops" descriptor and having the "set_ftrace_filter" and "set_ftrace_notrace" map to it.

When an instance is created, it creates the same files but its for the local instance and not the global_ops.

The issues is that the local instance creation shares some code with the global instance one and we end up trying to create th top level "set_ftrace_*" files twice, and on boot up, we get an error like this:

Could not create debugfs 'set_ftrace_filter' entry Could not create debugfs 'set_ftrace_notrace' entry

The reason they failed to be created was because they were created twice, and the second time gives this error as you can not create the same file twice.

---
 kernel/trace/trace_functions.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

index 5b781d2..ffd5635 100644
@@ -58,12 +58,16 @@ int ftrace_create_function_files(struct trace_array *tr,
 {
 	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;
-	}
+	/*
+	 * The top level array uses the "global_ops", and the files are
+	 * created on boot up.
+	 */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return 0;
+
+	ret = allocate_ftrace_ops(tr);
+	if (ret)
+		return ret;
 
 	ftrace_create_filter_files(tr->ops, parent);
 

1.8.5.3

From: "zhangwei(Jovi)" <[email protected]>

Forgot to free uprobe_cpu_buffer percpu page in uprobe_buffer_disable().

---
 kernel/trace/trace_uprobe.c | 6 ++++++
 1 file changed, 6 insertions(+)

index 930e514..c082a74 100644
@@ -732,9 +732,15 @@ static int uprobe_buffer_enable(void)
 
 static void uprobe_buffer_disable(void)
 {
+	int cpu;
+
 	BUG_ON(!mutex_is_locked(&event_mutex));
 
 	if (--uprobe_buffer_refcnt == 0) {
+		for_each_possible_cpu(cpu)
+			free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
+							     cpu)->buf);
+
 		free_percpu(uprobe_cpu_buffer);
 		uprobe_cpu_buffer = NULL;
 	}

1.8.5.3