Merge commit 'md/for-linus' into async-tx-next

Conflicts:
	drivers/md/raid5.c

15 files changed, 161 insertions, 119 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 1551f47e7669..019f380fd764 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -226,13 +226,13 @@ config BOOT_TRACER
 	  the timings of the initcalls and traces key events and the identity
 	  of tasks that can cause boot delays, such as context-switches.
 
-	  Its aim is to be parsed by the /scripts/bootgraph.pl tool to
+	  Its aim is to be parsed by the scripts/bootgraph.pl tool to
 	  produce pretty graphics about boot inefficiencies, giving a visual
 	  representation of the delays during initcalls - but the raw
 	  /debug/tracing/trace text output is readable too.
 
-	  You must pass in ftrace=initcall to the kernel command line
-	  to enable this on bootup.
+	  You must pass in initcall_debug and ftrace=initcall to the kernel
+	  command line to enable this on bootup.
 
 config TRACE_BRANCH_PROFILING
 	bool
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 39af8af6fc30..1090b0aed9ba 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -22,6 +22,7 @@
 #include <linux/init.h>
 #include <linux/mutex.h>
 #include <linux/debugfs.h>
+#include <linux/smp_lock.h>
 #include <linux/time.h>
 #include <linux/uaccess.h>
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3718d55fb4c3..1e1d23c26308 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -291,7 +291,9 @@ function_stat_next(void *v, int idx)
 	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 
  again:
-	rec++;
+	if (idx != 0)
+		rec++;
+
 	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 		pg = pg->next;
 		if (!pg)
@@ -766,7 +768,7 @@ static struct tracer_stat function_stats __initdata = {
 	.stat_show	= function_stat_show
 };
 
-static void ftrace_profile_debugfs(struct dentry *d_tracer)
+static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 {
 	struct ftrace_profile_stat *stat;
 	struct dentry *entry;
@@ -784,7 +786,6 @@ static void ftrace_profile_debugfs(struct dentry *d_tracer)
 			 * The files created are permanent, if something happens
 			 * we still do not free memory.
 			 */
-			kfree(stat);
 			WARN(1,
 			     "Could not allocate stat file for cpu %d\n",
 			     cpu);
@@ -811,7 +812,7 @@ static void ftrace_profile_debugfs(struct dentry *d_tracer)
 }
 
 #else /* CONFIG_FUNCTION_PROFILER */
-static void ftrace_profile_debugfs(struct dentry *d_tracer)
+static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 {
 }
 #endif /* CONFIG_FUNCTION_PROFILER */
@@ -1417,10 +1418,20 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	void *p = NULL;
+	loff_t l;
+
+	if (!(iter->flags & FTRACE_ITER_HASH))
+		*pos = 0;
 
 	iter->flags |= FTRACE_ITER_HASH;
 
-	return t_hash_next(m, p, pos);
+	iter->hidx = 0;
+	for (l = 0; l <= *pos; ) {
+		p = t_hash_next(m, p, &l);
+		if (!p)
+			break;
+	}
+	return p;
 }
 
 static int t_hash_show(struct seq_file *m, void *v)
@@ -1467,8 +1478,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 			iter->pg = iter->pg->next;
 			iter->idx = 0;
 			goto retry;
-		} else {
-			iter->idx = -1;
 		}
 	} else {
 		rec = &iter->pg->records[iter->idx++];
@@ -1497,6 +1506,7 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	void *p = NULL;
+	loff_t l;
 
 	mutex_lock(&ftrace_lock);
 	/*
@@ -1508,23 +1518,21 @@ static void *t_start(struct seq_file *m, loff_t *pos)
 		if (*pos > 0)
 			return t_hash_start(m, pos);
 		iter->flags |= FTRACE_ITER_PRINTALL;
-		(*pos)++;
 		return iter;
 	}
 
 	if (iter->flags & FTRACE_ITER_HASH)
 		return t_hash_start(m, pos);
 
-	if (*pos > 0) {
-		if (iter->idx < 0)
-			return p;
-		(*pos)--;
-		iter->idx--;
+	iter->pg = ftrace_pages_start;
+	iter->idx = 0;
+	for (l = 0; l <= *pos; ) {
+		p = t_next(m, p, &l);
+		if (!p)
+			break;
 	}
 
-	p = t_next(m, p, pos);
-
-	if (!p)
+	if (!p && iter->flags & FTRACE_ITER_FILTER)
 		return t_hash_start(m, pos);
 
 	return p;
@@ -1654,7 +1662,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
 	mutex_lock(&ftrace_regex_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND))
+	    (file->f_flags & O_TRUNC))
 		ftrace_filter_reset(enable);
 
 	if (file->f_mode & FMODE_READ) {
@@ -2500,32 +2508,31 @@ int ftrace_graph_count;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
 static void *
-g_next(struct seq_file *m, void *v, loff_t *pos)
+__g_next(struct seq_file *m, loff_t *pos)
 {
 	unsigned long *array = m->private;
-	int index = *pos;
-
-	(*pos)++;
 
-	if (index >= ftrace_graph_count)
+	if (*pos >= ftrace_graph_count)
 		return NULL;
+	return &array[*pos];
+}
 
-	return &array[index];
+static void *
+g_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return __g_next(m, pos);
 }
 
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
-	void *p = NULL;
-
 	mutex_lock(&graph_lock);
 
 	/* Nothing, tell g_show to print all functions are enabled */
 	if (!ftrace_graph_count && !*pos)
 		return (void *)1;
 
-	p = g_next(m, p, pos);
-
-	return p;
+	return __g_next(m, pos);
 }
 
 static void g_stop(struct seq_file *m, void *p)
@@ -2570,7 +2577,7 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 
 	mutex_lock(&graph_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND)) {
+	    (file->f_flags & O_TRUNC)) {
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}
@@ -2589,6 +2596,14 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 }
 
 static int
+ftrace_graph_release(struct inode *inode, struct file *file)
+{
+	if (file->f_mode & FMODE_READ)
+		seq_release(inode, file);
+	return 0;
+}
+
+static int
 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 {
 	struct dyn_ftrace *rec;
@@ -2717,9 +2732,10 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 }
 
 static const struct file_operations ftrace_graph_fops = {
-	.open = ftrace_graph_open,
-	.read = seq_read,
-	.write = ftrace_graph_write,
+	.open		= ftrace_graph_open,
+	.read		= seq_read,
+	.write		= ftrace_graph_write,
+	.release	= ftrace_graph_release,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -3152,10 +3168,10 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 
 	ret  = proc_dointvec(table, write, file, buffer, lenp, ppos);
 
-	if (ret || !write || (last_ftrace_enabled == ftrace_enabled))
+	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
 		goto out;
 
-	last_ftrace_enabled = ftrace_enabled;
+	last_ftrace_enabled = !!ftrace_enabled;
 
 	if (ftrace_enabled) {
 
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 04dac2638258..bf27bb7a63e2 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -1563,6 +1563,8 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
 	return NULL;
 }
 
+#ifdef CONFIG_TRACING
+
 #define TRACE_RECURSIVE_DEPTH 16
 
 static int trace_recursive_lock(void)
@@ -1593,6 +1595,13 @@ static void trace_recursive_unlock(void)
 	current->trace_recursion--;
 }
 
+#else
+
+#define trace_recursive_lock()		(0)
+#define trace_recursive_unlock()	do { } while (0)
+
+#endif
+
 static DEFINE_PER_CPU(int, rb_need_resched);
 
 /**
@@ -3104,6 +3113,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_page);
 
+#ifdef CONFIG_TRACING
 static ssize_t
 rb_simple_read(struct file *filp, char __user *ubuf,
 	       size_t cnt, loff_t *ppos)
@@ -3171,6 +3181,7 @@ static __init int rb_init_debugfs(void)
 }
 
 fs_initcall(rb_init_debugfs);
+#endif
 
 #ifdef CONFIG_HOTPLUG_CPU
 static int rb_cpu_notify(struct notifier_block *self,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 076fa6f0ee48..8930e39b9d8c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -17,6 +17,7 @@
 #include <linux/writeback.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
+#include <linux/smp_lock.h>
 #include <linux/notifier.h>
 #include <linux/irqflags.h>
 #include <linux/debugfs.h>
@@ -284,13 +285,12 @@ void trace_wake_up(void)
 static int __init set_buf_size(char *str)
 {
 	unsigned long buf_size;
-	int ret;
 
 	if (!str)
 		return 0;
-	ret = strict_strtoul(str, 0, &buf_size);
+	buf_size = memparse(str, &str);
 	/* nr_entries can not be zero */
-	if (ret < 0 || buf_size == 0)
+	if (buf_size == 0)
 		return 0;
 	trace_buf_size = buf_size;
 	return 1;
@@ -2031,7 +2031,7 @@ static int tracing_open(struct inode *inode, struct file *file)
 
 	/* If this file was open for write, then erase contents */
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND)) {
+	    (file->f_flags & O_TRUNC)) {
 		long cpu = (long) inode->i_private;
 
 		if (cpu == TRACE_PIPE_ALL_CPU)
@@ -2053,25 +2053,23 @@ static int tracing_open(struct inode *inode, struct file *file)
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	struct tracer *t = m->private;
+	struct tracer *t = v;
 
 	(*pos)++;
 
 	if (t)
 		t = t->next;
 
-	m->private = t;
-
 	return t;
 }
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-	struct tracer *t = m->private;
+	struct tracer *t;
 	loff_t l = 0;
 
 	mutex_lock(&trace_types_lock);
-	for (; t && l < *pos; t = t_next(m, t, &l))
+	for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
 		;
 
 	return t;
@@ -2107,18 +2105,10 @@ static struct seq_operations show_traces_seq_ops = {
 
 static int show_traces_open(struct inode *inode, struct file *file)
 {
-	int ret;
-
 	if (tracing_disabled)
 		return -ENODEV;
 
-	ret = seq_open(file, &show_traces_seq_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		m->private = trace_types;
-	}
-
-	return ret;
+	return seq_open(file, &show_traces_seq_ops);
 }
 
 static ssize_t
@@ -3095,7 +3085,8 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
 			break;
 		}
 
-		trace_consume(iter);
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
 		rem -= count;
 		if (!find_next_entry_inc(iter))	{
 			rem = 0;
@@ -4243,8 +4234,11 @@ static void __ftrace_dump(bool disable_tracing)
 		iter.pos = -1;
 
 		if (find_next_entry_inc(&iter) != NULL) {
-			print_trace_line(&iter);
-			trace_consume(&iter);
+			int ret;
+
+			ret = print_trace_line(&iter);
+			if (ret != TRACE_TYPE_NO_CONSUME)
+				trace_consume(&iter);
 		}
 
 		trace_printk_seq(&iter.seq);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6e735d4771f8..3548ae5cc780 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -597,6 +597,7 @@ print_graph_function(struct trace_iterator *iter)
 
 extern struct pid *ftrace_pid_trace;
 
+#ifdef CONFIG_FUNCTION_TRACER
 static inline int ftrace_trace_task(struct task_struct *task)
 {
 	if (!ftrace_pid_trace)
@@ -604,6 +605,12 @@ static inline int ftrace_trace_task(struct task_struct *task)
 
 	return test_tsk_trace_trace(task);
 }
+#else
+static inline int ftrace_trace_task(struct task_struct *task)
+{
+	return 1;
+}
+#endif
 
 /*
  * trace_iterator_flags is an enumeration that defines bit
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 5b5895afecfe..11ba5bb4ed0a 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -14,7 +14,7 @@ int ftrace_profile_enable(int event_id)
 
 	mutex_lock(&event_mutex);
 	list_for_each_entry(event, &ftrace_events, list) {
-		if (event->id == event_id) {
+		if (event->id == event_id && event->profile_enable) {
 			ret = event->profile_enable(event);
 			break;
 		}
diff --git a/kernel/trace/trace_event_types.h b/kernel/trace/trace_event_types.h
index 5e32e375134d..6db005e12487 100644
--- a/kernel/trace/trace_event_types.h
+++ b/kernel/trace/trace_event_types.h
@@ -26,6 +26,9 @@ TRACE_EVENT_FORMAT(funcgraph_exit, TRACE_GRAPH_RET,
 		   ftrace_graph_ret_entry, ignore,
 	TRACE_STRUCT(
 		TRACE_FIELD(unsigned long, ret.func, func)
+		TRACE_FIELD(unsigned long long, ret.calltime, calltime)
+		TRACE_FIELD(unsigned long long, ret.rettime, rettime)
+		TRACE_FIELD(unsigned long, ret.overrun, overrun)
 		TRACE_FIELD(int, ret.depth, depth)
 	),
 	TP_RAW_FMT("<-- %lx (%d)")
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index aa08be69a1b6..e75276a49cf5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -300,10 +300,18 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
+	struct ftrace_event_call *call = NULL;
+	loff_t l;
+
 	mutex_lock(&event_mutex);
-	if (*pos == 0)
-		m->private = ftrace_events.next;
-	return t_next(m, NULL, pos);
+
+	m->private = ftrace_events.next;
+	for (l = 0; l <= *pos; ) {
+		call = t_next(m, NULL, &l);
+		if (!call)
+			break;
+	}
+	return call;
 }
 
 static void *
@@ -332,10 +340,18 @@ s_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
+	struct ftrace_event_call *call = NULL;
+	loff_t l;
+
 	mutex_lock(&event_mutex);
-	if (*pos == 0)
-		m->private = ftrace_events.next;
-	return s_next(m, NULL, pos);
+
+	m->private = ftrace_events.next;
+	for (l = 0; l <= *pos; ) {
+		call = s_next(m, NULL, &l);
+		if (!call)
+			break;
+	}
+	return call;
 }
 
 static int t_show(struct seq_file *m, void *v)
@@ -360,7 +376,7 @@ ftrace_event_seq_open(struct inode *inode, struct file *file)
 	const struct seq_operations *seq_ops;
 
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND))
+	    (file->f_flags & O_TRUNC))
 		ftrace_clear_events();
 
 	seq_ops = inode->i_private;
@@ -924,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 		entry = trace_create_file("enable", 0644, call->dir, call,
 					  enable);
 
-	if (call->id)
+	if (call->id && call->profile_enable)
 		entry = trace_create_file("id", 0444, call->dir, call,
 					  id);
 
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 90f134764837..75ef000613c3 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -302,8 +302,7 @@ ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
 	if (count == -1)
 		seq_printf(m, ":unlimited\n");
 	else
-		seq_printf(m, ":count=%ld", count);
-	seq_putc(m, '\n');
+		seq_printf(m, ":count=%ld\n", count);
 
 	return 0;
 }
@@ -364,7 +363,7 @@ ftrace_trace_onoff_callback(char *glob, char *cmd, char *param, int enable)
  out_reg:
 	ret = register_ftrace_function_probe(glob, ops, count);
 
-	return ret;
+	return ret < 0 ? ret : 0;
 }
 
 static struct ftrace_func_command ftrace_traceon_cmd = {
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index d2249abafb53..420ec3487579 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -843,9 +843,16 @@ print_graph_function(struct trace_iterator *iter)
 
 	switch (entry->type) {
 	case TRACE_GRAPH_ENT: {
-		struct ftrace_graph_ent_entry *field;
+		/*
+		 * print_graph_entry() may consume the current event,
+		 * thus @field may become invalid, so we need to save it.
+		 * sizeof(struct ftrace_graph_ent_entry) is very small,
+		 * it can be safely saved at the stack.
+		 */
+		struct ftrace_graph_ent_entry *field, saved;
 		trace_assign_type(field, entry);
-		return print_graph_entry(field, s, iter);
+		saved = *field;
+		return print_graph_entry(&saved, s, iter);
 	}
 	case TRACE_GRAPH_RET: {
 		struct ftrace_graph_ret_entry *field;
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 7938f3ae93e3..e0c2545622e8 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -27,8 +27,7 @@ void trace_print_seq(struct seq_file *m, struct trace_seq *s)
 {
 	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
 
-	s->buffer[len] = 0;
-	seq_puts(m, s->buffer);
+	seq_write(m, s->buffer, len);
 
 	trace_seq_init(s);
 }
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 9bece9687b62..687699d365ae 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -155,25 +155,19 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
 
 static void *
-t_next(struct seq_file *m, void *v, loff_t *pos)
+t_start(struct seq_file *m, loff_t *pos)
 {
-	const char **fmt = m->private;
-	const char **next = fmt;
-
-	(*pos)++;
+	const char **fmt = __start___trace_bprintk_fmt + *pos;
 
 	if ((unsigned long)fmt >= (unsigned long)__stop___trace_bprintk_fmt)
 		return NULL;
-
-	next = fmt;
-	m->private = ++next;
-
 	return fmt;
 }
 
-static void *t_start(struct seq_file *m, loff_t *pos)
+static void *t_next(struct seq_file *m, void * v, loff_t *pos)
 {
-	return t_next(m, NULL, pos);
+	(*pos)++;
+	return t_start(m, pos);
 }
 
 static int t_show(struct seq_file *m, void *v)
@@ -182,7 +176,7 @@ static int t_show(struct seq_file *m, void *v)
 	const char *str = *fmt;
 	int i;
 
-	seq_printf(m, "0x%lx : \"", (unsigned long)fmt);
+	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
 
 	/*
 	 * Tabs and new lines need to be converted.
@@ -224,15 +218,7 @@ static const struct seq_operations show_format_seq_ops = {
 static int
 ftrace_formats_open(struct inode *inode, struct file *file)
 {
-	int ret;
-
-	ret = seq_open(file, &show_format_seq_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-
-		m->private = __start___trace_bprintk_fmt;
-	}
-	return ret;
+	return seq_open(file, &show_format_seq_ops);
 }
 
 static const struct file_operations ftrace_formats_fops = {
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 2d7aebd71dbd..6a2a9d484cd6 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -301,17 +301,14 @@ static const struct seq_operations stack_trace_seq_ops = {
 
 static int stack_trace_open(struct inode *inode, struct file *file)
 {
-	int ret;
-
-	ret = seq_open(file, &stack_trace_seq_ops);
-
-	return ret;
+	return seq_open(file, &stack_trace_seq_ops);
 }
 
 static const struct file_operations stack_trace_fops = {
 	.open		= stack_trace_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
+	.release	= seq_release,
 };
 
 int
@@ -326,10 +323,10 @@ stack_trace_sysctl(struct ctl_table *table, int write,
 	ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
 
 	if (ret || !write ||
-	    (last_stack_tracer_enabled == stack_tracer_enabled))
+	    (last_stack_tracer_enabled == !!stack_tracer_enabled))
 		goto out;
 
-	last_stack_tracer_enabled = stack_tracer_enabled;
+	last_stack_tracer_enabled = !!stack_tracer_enabled;
 
 	if (stack_tracer_enabled)
 		register_ftrace_function(&trace_ops);
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index c00643733f4c..aea321c82fa0 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -73,7 +73,7 @@ static struct rb_node *release_next(struct rb_node *node)
 	}
 }
 
-static void reset_stat_session(struct stat_session *session)
+static void __reset_stat_session(struct stat_session *session)
 {
 	struct rb_node *node = session->stat_root.rb_node;
 
@@ -83,10 +83,17 @@ static void reset_stat_session(struct stat_session *session)
 	session->stat_root = RB_ROOT;
 }
 
+static void reset_stat_session(struct stat_session *session)
+{
+	mutex_lock(&session->stat_mutex);
+	__reset_stat_session(session);
+	mutex_unlock(&session->stat_mutex);
+}
+
 static void destroy_session(struct stat_session *session)
 {
 	debugfs_remove(session->file);
-	reset_stat_session(session);
+	__reset_stat_session(session);
 	mutex_destroy(&session->stat_mutex);
 	kfree(session);
 }
@@ -150,7 +157,7 @@ static int stat_seq_init(struct stat_session *session)
 	int i;
 
 	mutex_lock(&session->stat_mutex);
-	reset_stat_session(session);
+	__reset_stat_session(session);
 
 	if (!ts->stat_cmp)
 		ts->stat_cmp = dummy_cmp;
@@ -183,7 +190,7 @@ exit:
 	return ret;
 
 exit_free_rbtree:
-	reset_stat_session(session);
+	__reset_stat_session(session);
 	mutex_unlock(&session->stat_mutex);
 	return ret;
 }
@@ -199,17 +206,13 @@ static void *stat_seq_start(struct seq_file *s, loff_t *pos)
 	mutex_lock(&session->stat_mutex);
 
 	/* If we are in the beginning of the file, print the headers */
-	if (!*pos && session->ts->stat_headers) {
-		(*pos)++;
+	if (!*pos && session->ts->stat_headers)
 		return SEQ_START_TOKEN;
-	}
 
 	node = rb_first(&session->stat_root);
 	for (i = 0; node && i < *pos; i++)
 		node = rb_next(node);
 
-	(*pos)++;
-
 	return node;
 }
 
@@ -254,16 +257,21 @@ static const struct seq_operations trace_stat_seq_ops = {
 static int tracing_stat_open(struct inode *inode, struct file *file)
 {
 	int ret;
-
+	struct seq_file *m;
 	struct stat_session *session = inode->i_private;
 
+	ret = stat_seq_init(session);
+	if (ret)
+		return ret;
+
 	ret = seq_open(file, &trace_stat_seq_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		m->private = session;
-		ret = stat_seq_init(session);
+	if (ret) {
+		reset_stat_session(session);
+		return ret;
 	}
 
+	m = file->private_data;
+	m->private = session;
 	return ret;
 }
 
@@ -274,11 +282,9 @@ static int tracing_stat_release(struct inode *i, struct file *f)
 {
 	struct stat_session *session = i->i_private;
 
-	mutex_lock(&session->stat_mutex);
 	reset_stat_session(session);
-	mutex_unlock(&session->stat_mutex);
 
-	return 0;
+	return seq_release(i, f);
 }
 
 static const struct file_operations tracing_stat_fops = {