Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (241 commits)
  sched, trace: update trace_sched_wakeup()
  tracing/ftrace: don't trace on early stage of a secondary cpu boot, v3
  Revert "x86: disable X86_PTRACE_BTS"
  ring-buffer: prevent false positive warning
  ring-buffer: fix dangling commit race
  ftrace: enable format arguments checking
  x86, bts: memory accounting
  x86, bts: add fork and exit handling
  ftrace: introduce tracing_reset_online_cpus() helper
  tracing: fix warnings in kernel/trace/trace_sched_switch.c
  tracing: fix warning in kernel/trace/trace.c
  tracing/ring-buffer: remove unused ring_buffer size
  trace: fix task state printout
  ftrace: add not to regex on filtering functions
  trace: better use of stack_trace_enabled for boot up code
  trace: add a way to enable or disable the stack tracer
  x86: entry_64 - introduce FTRACE_ frame macro v2
  tracing/ftrace: add the printk-msg-only option
  tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp()
  x86, bts: correctly report invalid bts records
  ...

Fixed up trivial conflict in scripts/recordmcount.pl due to SH bits
being already partly merged by the SH merge.

1 files changed, 55 insertions, 15 deletions

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3bdb44bde4b7..d0871bc0aca5 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -10,6 +10,7 @@
 #include <linux/debugfs.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
+#include <linux/sysctl.h>
 #include <linux/init.h>
 #include <linux/fs.h>
 #include "trace.h"
@@ -31,6 +32,10 @@ static raw_spinlock_t max_stack_lock =
 
 static int stack_trace_disabled __read_mostly;
 static DEFINE_PER_CPU(int, trace_active);
+static DEFINE_MUTEX(stack_sysctl_mutex);
+
+int stack_tracer_enabled;
+static int last_stack_tracer_enabled;
 
 static inline void check_stack(void)
 {
@@ -48,7 +53,7 @@ static inline void check_stack(void)
 	if (!object_is_on_stack(&this_size))
 		return;
 
-	raw_local_irq_save(flags);
+	local_irq_save(flags);
 	__raw_spin_lock(&max_stack_lock);
 
 	/* a race could have already updated it */
@@ -78,6 +83,7 @@ static inline void check_stack(void)
 	 * on a new max, so it is far from a fast path.
 	 */
 	while (i < max_stack_trace.nr_entries) {
+		int found = 0;
 
 		stack_dump_index[i] = this_size;
 		p = start;
@@ -86,17 +92,19 @@ static inline void check_stack(void)
 			if (*p == stack_dump_trace[i]) {
 				this_size = stack_dump_index[i++] =
 					(top - p) * sizeof(unsigned long);
+				found = 1;
 				/* Start the search from here */
 				start = p + 1;
 			}
 		}
 
-		i++;
+		if (!found)
+			i++;
 	}
 
  out:
 	__raw_spin_unlock(&max_stack_lock);
-	raw_local_irq_restore(flags);
+	local_irq_restore(flags);
 }
 
 static void
@@ -107,8 +115,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
 	if (unlikely(!ftrace_enabled || stack_trace_disabled))
 		return;
 
-	resched = need_resched();
-	preempt_disable_notrace();
+	resched = ftrace_preempt_disable();
 
 	cpu = raw_smp_processor_id();
 	/* no atomic needed, we only modify this variable by this cpu */
@@ -120,10 +127,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
  out:
 	per_cpu(trace_active, cpu)--;
 	/* prevent recursion in schedule */
-	if (resched)
-		preempt_enable_no_resched_notrace();
-	else
-		preempt_enable_notrace();
+	ftrace_preempt_enable(resched);
 }
 
 static struct ftrace_ops trace_ops __read_mostly =
@@ -166,16 +170,16 @@ stack_max_size_write(struct file *filp, const char __user *ubuf,
 	if (ret < 0)
 		return ret;
 
-	raw_local_irq_save(flags);
+	local_irq_save(flags);
 	__raw_spin_lock(&max_stack_lock);
 	*ptr = val;
 	__raw_spin_unlock(&max_stack_lock);
-	raw_local_irq_restore(flags);
+	local_irq_restore(flags);
 
 	return count;
 }
 
-static struct file_operations stack_max_size_fops = {
+static const struct file_operations stack_max_size_fops = {
 	.open		= tracing_open_generic,
 	.read		= stack_max_size_read,
 	.write		= stack_max_size_write,
@@ -273,7 +277,7 @@ static int t_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-static struct seq_operations stack_trace_seq_ops = {
+static const struct seq_operations stack_trace_seq_ops = {
 	.start		= t_start,
 	.next		= t_next,
 	.stop		= t_stop,
@@ -289,12 +293,47 @@ static int stack_trace_open(struct inode *inode, struct file *file)
 	return ret;
 }
 
-static struct file_operations stack_trace_fops = {
+static const struct file_operations stack_trace_fops = {
 	.open		= stack_trace_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 };
 
+int
+stack_trace_sysctl(struct ctl_table *table, int write,
+		   struct file *file, void __user *buffer, size_t *lenp,
+		   loff_t *ppos)
+{
+	int ret;
+
+	mutex_lock(&stack_sysctl_mutex);
+
+	ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
+
+	if (ret || !write ||
+	    (last_stack_tracer_enabled == stack_tracer_enabled))
+		goto out;
+
+	last_stack_tracer_enabled = stack_tracer_enabled;
+
+	if (stack_tracer_enabled)
+		register_ftrace_function(&trace_ops);
+	else
+		unregister_ftrace_function(&trace_ops);
+
+ out:
+	mutex_unlock(&stack_sysctl_mutex);
+	return ret;
+}
+
+static __init int enable_stacktrace(char *str)
+{
+	stack_tracer_enabled = 1;
+	last_stack_tracer_enabled = 1;
+	return 1;
+}
+__setup("stacktrace", enable_stacktrace);
+
 static __init int stack_trace_init(void)
 {
 	struct dentry *d_tracer;
@@ -312,7 +351,8 @@ static __init int stack_trace_init(void)
 	if (!entry)
 		pr_warning("Could not create debugfs 'stack_trace' entry\n");
 
-	register_ftrace_function(&trace_ops);
+	if (stack_tracer_enabled)
+		register_ftrace_function(&trace_ops);
 
 	return 0;
 }