5 files changed, 46 insertions, 8 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2f32969c09d..9a236ffe2aa 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -17,6 +17,7 @@
 #include <linux/clocksource.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
+#include <linux/suspend.h>
 #include <linux/debugfs.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
@@ -1736,9 +1737,12 @@ static void clear_ftrace_pid(struct pid *pid)
 {
 	struct task_struct *p;
 
+	rcu_read_lock();
 	do_each_pid_task(pid, PIDTYPE_PID, p) {
 		clear_tsk_trace_trace(p);
 	} while_each_pid_task(pid, PIDTYPE_PID, p);
+	rcu_read_unlock();
+
 	put_pid(pid);
 }
 
@@ -1746,9 +1750,11 @@ static void set_ftrace_pid(struct pid *pid)
 {
 	struct task_struct *p;
 
+	rcu_read_lock();
 	do_each_pid_task(pid, PIDTYPE_PID, p) {
 		set_tsk_trace_trace(p);
 	} while_each_pid_task(pid, PIDTYPE_PID, p);
+	rcu_read_unlock();
 }
 
 static void clear_ftrace_pid_task(struct pid **pid)
@@ -1965,6 +1971,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 static atomic_t ftrace_graph_active;
+static struct notifier_block ftrace_suspend_notifier;
 
 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
 {
@@ -2043,6 +2050,27 @@ static int start_graph_tracing(void)
 	return ret;
 }
 
+/*
+ * Hibernation protection.
+ * The state of the current task is too much unstable during
+ * suspend/restore to disk. We want to protect against that.
+ */
+static int
+ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
+							void *unused)
+{
+	switch (state) {
+	case PM_HIBERNATION_PREPARE:
+		pause_graph_tracing();
+		break;
+
+	case PM_POST_HIBERNATION:
+		unpause_graph_tracing();
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 			trace_func_graph_ent_t entryfunc)
 {
@@ -2050,6 +2078,9 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 
 	mutex_lock(&ftrace_sysctl_lock);
 
+	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
+	register_pm_notifier(&ftrace_suspend_notifier);
+
 	atomic_inc(&ftrace_graph_active);
 	ret = start_graph_tracing();
 	if (ret) {
@@ -2075,6 +2106,7 @@ void unregister_ftrace_graph(void)
 	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
 	ftrace_graph_entry = ftrace_graph_entry_stub;
 	ftrace_shutdown(FTRACE_STOP_FUNC_RET);
+	unregister_pm_notifier(&ftrace_suspend_notifier);
 
 	mutex_unlock(&ftrace_sysctl_lock);
 }
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 8b0daf0662e..bd38c5cfd8a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -246,7 +246,7 @@ static inline int test_time_stamp(u64 delta)
 	return 0;
 }
 
-#define BUF_PAGE_SIZE (PAGE_SIZE - sizeof(struct buffer_data_page))
+#define BUF_PAGE_SIZE (PAGE_SIZE - offsetof(struct buffer_data_page, data))
 
 /*
  * head_page == tail_page && head == tail then buffer is empty.
@@ -1025,12 +1025,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 		}
 
 		if (next_page == head_page) {
-			if (!(buffer->flags & RB_FL_OVERWRITE)) {
-				/* reset write */
-				if (tail <= BUF_PAGE_SIZE)
-					local_set(&tail_page->write, tail);
+			if (!(buffer->flags & RB_FL_OVERWRITE))
 				goto out_unlock;
-			}
 
 			/* tail_page has not moved yet? */
 			if (tail_page == cpu_buffer->tail_page) {
@@ -1105,6 +1101,10 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 	return event;
 
  out_unlock:
+	/* reset write */
+	if (tail <= BUF_PAGE_SIZE)
+		local_set(&tail_page->write, tail);
+
 	__raw_spin_unlock(&cpu_buffer->lock);
 	local_irq_restore(flags);
 	return NULL;
@@ -2174,6 +2174,9 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
 
 	cpu_buffer->overrun = 0;
 	cpu_buffer->entries = 0;
+
+	cpu_buffer->write_stamp = 0;
+	cpu_buffer->read_stamp = 0;
 }
 
 /**
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c580233add9..17bb88d86ac 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -40,7 +40,7 @@
 
 #define TRACE_BUFFER_FLAGS	(RB_FL_OVERWRITE)
 
-unsigned long __read_mostly	tracing_max_latency = (cycle_t)ULONG_MAX;
+unsigned long __read_mostly	tracing_max_latency;
 unsigned long __read_mostly	tracing_thresh;
 
 /*
@@ -3736,7 +3736,7 @@ static struct notifier_block trace_die_notifier = {
  * it if we decide to change what log level the ftrace dump
  * should be at.
  */
-#define KERN_TRACE		KERN_INFO
+#define KERN_TRACE		KERN_EMERG
 
 static void
 trace_printk_seq(struct trace_seq *s)
@@ -3770,6 +3770,7 @@ void ftrace_dump(void)
 	dump_ran = 1;
 
 	/* No turning back! */
+	tracing_off();
 	ftrace_kill();
 
 	for_each_tracing_cpu(cpu) {
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 7c2e326bbc8..62a78d94353 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -380,6 +380,7 @@ static void stop_irqsoff_tracer(struct trace_array *tr)
 
 static void __irqsoff_tracer_init(struct trace_array *tr)
 {
+	tracing_max_latency = 0;
 	irqsoff_trace = tr;
 	/* make sure that the tracer is visible */
 	smp_wmb();
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 43586b689e3..42ae1e77b6b 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -333,6 +333,7 @@ static void stop_wakeup_tracer(struct trace_array *tr)
 
 static int wakeup_tracer_init(struct trace_array *tr)
 {
+	tracing_max_latency = 0;
 	wakeup_trace = tr;
 	start_wakeup_tracer(tr);
 	return 0;