[for-next][PATCH 00/13] tracing: More updates for 4.5.

[for-next][PATCH 00/13] tracing: More updates for 4.5.

[Steven Rostedt]

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
for-next

Head SHA1: 05a724bd44a68cd5c60bc4b949a946b57d4c9e55


Abel Vesa (1):
      ftrace: Join functions ftrace_module_init() and ftrace_init_module()

Chuyu Hu (1):
      tracing: Fix comment to use tracing_on over tracing_enable

Denis Kirjanov (1):
      tracing: Introduce TRACE_EVENT_FN_COND macro

Jerry Snitselaar (1):
      tracing: Use seq_buf_used() in seq_buf_to_user() instead of len

Julia Lawall (1):
      bpf: Constify bpf_verifier_ops structure

Li Bin (4):
      ftrace: Fix a typo in comment
      ia64: ftrace: Fix the comments for ftrace_modify_code()
      sh: ftrace: Fix the comments for ftrace_modify_code()
      metag: ftrace: Fix the comments for ftrace_modify_code

Steven Rostedt (Red Hat) (4):
      ftrace: Fix output of enabled_functions for showing tramp
      ftrace: Remove use of control list and ops
      ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too
      ftrace: Clean up ftrace_module_init() code

----
 arch/ia64/kernel/ftrace.c       |  12 ++-
 arch/metag/kernel/ftrace.c      |  11 ++-
 arch/sh/kernel/ftrace.c         |  12 ++-
 include/linux/ftrace.h          |  35 ++++----
 include/linux/tracepoint.h      |   4 +
 include/trace/define_trace.h    |   6 ++
 include/trace/trace_events.h    |   6 ++
 kernel/trace/bpf_trace.c        |   2 +-
 kernel/trace/ftrace.c           | 179 +++++++++++++++-------------------------
 kernel/trace/trace.h            |   6 +-
 kernel/trace/trace_event_perf.c |   2 +-
 lib/seq_buf.c                   |   6 +-
 12 files changed, 122 insertions(+), 159 deletions(-)

[for-next][PATCH 01/13] ftrace: Fix a typo in comment

[Steven Rostedt]

[-- Attachment #1: 0001-ftrace-Fix-a-typo-in-comment.patch --]
[-- Type: text/plain, Size: 940 bytes --]

From: Li Bin <huawei.libin@huawei.com>

s/ARCH_SUPPORT_FTARCE_OPS/ARCH_SUPPORTS_FTRACE_OPS/

Link: http://lkml.kernel.org/r/1448879016-8659-1-git-send-email-huawei.libin@huawei.com

Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e371aed51fcf..b8dfe8138aa2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5263,7 +5263,7 @@ out:
  * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
  * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
  * An architecture can pass partial regs with ftrace_ops and still
- * set the ARCH_SUPPORT_FTARCE_OPS.
+ * set the ARCH_SUPPORTS_FTRACE_OPS.
  */
 #if ARCH_SUPPORTS_FTRACE_OPS
 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
-- 
2.6.2

[for-next][PATCH 02/13] ftrace: Fix output of enabled_functions for showing tramp

[Steven Rostedt]

[-- Attachment #1: 0002-ftrace-Fix-output-of-enabled_functions-for-showing-t.patch --]
[-- Type: text/plain, Size: 1696 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

When showing all tramps registered to a ftrace record in the file
enabled_functions, it exits the loop with ops == NULL. But then it is
suppose to show the function on the ops->trampoline and
add_trampoline_func() is called with the given ops. But because ops is now
NULL (to exit the loop), it always shows the static trampoline instead of
the one that is really registered to the record.

The call to add_trampoline_func() that shows the trampoline for the given
ops needs to be called at every iteration.

Fixes: 39daa7b9e895 "ftrace: Show all tramps registered to a record on ftrace_bug()"
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b8dfe8138aa2..bf7bebcdad82 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3322,7 +3322,7 @@ static int t_show(struct seq_file *m, void *v)
 
 	seq_printf(m, "%ps", (void *)rec->ip);
 	if (iter->flags & FTRACE_ITER_ENABLED) {
-		struct ftrace_ops *ops = NULL;
+		struct ftrace_ops *ops;
 
 		seq_printf(m, " (%ld)%s%s",
 			   ftrace_rec_count(rec),
@@ -3335,13 +3335,14 @@ static int t_show(struct seq_file *m, void *v)
 					seq_printf(m, "\ttramp: %pS (%pS)",
 						   (void *)ops->trampoline,
 						   (void *)ops->func);
+					add_trampoline_func(m, ops, rec);
 					ops = ftrace_find_tramp_ops_next(rec, ops);
 				} while (ops);
 			} else
 				seq_puts(m, "\ttramp: ERROR!");
-
+		} else {
+			add_trampoline_func(m, NULL, rec);
 		}
-		add_trampoline_func(m, ops, rec);
 	}	
 
 	seq_putc(m, '\n');
-- 
2.6.2

[for-next][PATCH 03/13] ftrace: Remove use of control list and ops

[Steven Rostedt]

[-- Attachment #1: 0003-ftrace-Remove-use-of-control-list-and-ops.patch --]
[-- Type: text/plain, Size: 14870 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Currently perf has its own list function within the ftrace infrastructure
that seems to be used only to allow for it to have per-cpu disabling as well
as a check to make sure that it's not called while RCU is not watching. It
uses something called the "control_ops" which is used to iterate over ops
under it with the control_list_func().

The problem is that this control_ops and control_list_func unnecessarily
complicates the code. By replacing FTRACE_OPS_FL_CONTROL with two new flags
(FTRACE_OPS_FL_RCU and FTRACE_OPS_FL_PER_CPU) we can remove all the code
that is special with the control ops and add the needed checks within the
generic ftrace_list_func().

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace.h          |  35 +++++------
 kernel/trace/ftrace.c           | 126 ++++++++++++----------------------------
 kernel/trace/trace.h            |   2 -
 kernel/trace/trace_event_perf.c |   2 +-
 4 files changed, 57 insertions(+), 108 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 134f8d45b35b..4736a826baf5 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -76,8 +76,8 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
  * ENABLED - set/unset when ftrace_ops is registered/unregistered
  * DYNAMIC - set when ftrace_ops is registered to denote dynamically
  *           allocated ftrace_ops which need special care
- * CONTROL - set manualy by ftrace_ops user to denote the ftrace_ops
- *           could be controled by following calls:
+ * PER_CPU - set manualy by ftrace_ops user to denote the ftrace_ops
+ *           could be controlled by following calls:
  *             ftrace_function_local_enable
  *             ftrace_function_local_disable
  * SAVE_REGS - The ftrace_ops wants regs saved at each function called
@@ -121,7 +121,7 @@ ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops);
 enum {
 	FTRACE_OPS_FL_ENABLED			= 1 << 0,
 	FTRACE_OPS_FL_DYNAMIC			= 1 << 1,
-	FTRACE_OPS_FL_CONTROL			= 1 << 2,
+	FTRACE_OPS_FL_PER_CPU			= 1 << 2,
 	FTRACE_OPS_FL_SAVE_REGS			= 1 << 3,
 	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 4,
 	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 5,
@@ -134,6 +134,7 @@ enum {
 	FTRACE_OPS_FL_ALLOC_TRAMP		= 1 << 12,
 	FTRACE_OPS_FL_IPMODIFY			= 1 << 13,
 	FTRACE_OPS_FL_PID			= 1 << 14,
+	FTRACE_OPS_FL_RCU			= 1 << 15,
 };
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -146,11 +147,11 @@ struct ftrace_ops_hash {
 #endif
 
 /*
- * Note, ftrace_ops can be referenced outside of RCU protection.
- * (Although, for perf, the control ops prevent that). If ftrace_ops is
- * allocated and not part of kernel core data, the unregistering of it will
- * perform a scheduling on all CPUs to make sure that there are no more users.
- * Depending on the load of the system that may take a bit of time.
+ * Note, ftrace_ops can be referenced outside of RCU protection, unless
+ * the RCU flag is set. If ftrace_ops is allocated and not part of kernel
+ * core data, the unregistering of it will perform a scheduling on all CPUs
+ * to make sure that there are no more users. Depending on the load of the
+ * system that may take a bit of time.
  *
  * Any private data added must also take care not to be freed and if private
  * data is added to a ftrace_ops that is in core code, the user of the
@@ -196,34 +197,34 @@ int unregister_ftrace_function(struct ftrace_ops *ops);
 void clear_ftrace_function(void);
 
 /**
- * ftrace_function_local_enable - enable controlled ftrace_ops on current cpu
+ * ftrace_function_local_enable - enable ftrace_ops on current cpu
  *
  * This function enables tracing on current cpu by decreasing
  * the per cpu control variable.
  * It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
  */
 static inline void ftrace_function_local_enable(struct ftrace_ops *ops)
 {
-	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
+	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 		return;
 
 	(*this_cpu_ptr(ops->disabled))--;
 }
 
 /**
- * ftrace_function_local_disable - enable controlled ftrace_ops on current cpu
+ * ftrace_function_local_disable - disable ftrace_ops on current cpu
  *
- * This function enables tracing on current cpu by decreasing
+ * This function disables tracing on current cpu by increasing
  * the per cpu control variable.
  * It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
  */
 static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
 {
-	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL)))
+	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
 		return;
 
 	(*this_cpu_ptr(ops->disabled))++;
@@ -235,12 +236,12 @@ static inline void ftrace_function_local_disable(struct ftrace_ops *ops)
  *
  * This function returns value of ftrace_ops::disabled on current cpu.
  * It must be called with preemption disabled and only on ftrace_ops
- * registered with FTRACE_OPS_FL_CONTROL. If called without preemption
+ * registered with FTRACE_OPS_FL_PER_CPU. If called without preemption
  * disabled, this_cpu_ptr will complain when CONFIG_DEBUG_PREEMPT is enabled.
  */
 static inline int ftrace_function_local_disabled(struct ftrace_ops *ops)
 {
-	WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_CONTROL));
+	WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU));
 	return *this_cpu_ptr(ops->disabled);
 }
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bf7bebcdad82..bc7f4eb6b4b0 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -62,8 +62,6 @@
 #define FTRACE_HASH_DEFAULT_BITS 10
 #define FTRACE_HASH_MAX_BITS 12
 
-#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_CONTROL)
-
 #ifdef CONFIG_DYNAMIC_FTRACE
 #define INIT_OPS_HASH(opsname)	\
 	.func_hash		= &opsname.local_hash,			\
@@ -113,11 +111,9 @@ static int ftrace_disabled __read_mostly;
 
 static DEFINE_MUTEX(ftrace_lock);
 
-static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
 static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 static struct ftrace_ops global_ops;
-static struct ftrace_ops control_ops;
 
 static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
 				   struct ftrace_ops *op, struct pt_regs *regs);
@@ -203,7 +199,7 @@ void clear_ftrace_function(void)
 	ftrace_trace_function = ftrace_stub;
 }
 
-static void control_ops_disable_all(struct ftrace_ops *ops)
+static void per_cpu_ops_disable_all(struct ftrace_ops *ops)
 {
 	int cpu;
 
@@ -211,16 +207,19 @@ static void control_ops_disable_all(struct ftrace_ops *ops)
 		*per_cpu_ptr(ops->disabled, cpu) = 1;
 }
 
-static int control_ops_alloc(struct ftrace_ops *ops)
+static int per_cpu_ops_alloc(struct ftrace_ops *ops)
 {
 	int __percpu *disabled;
 
+	if (WARN_ON_ONCE(!(ops->flags & FTRACE_OPS_FL_PER_CPU)))
+		return -EINVAL;
+
 	disabled = alloc_percpu(int);
 	if (!disabled)
 		return -ENOMEM;
 
 	ops->disabled = disabled;
-	control_ops_disable_all(ops);
+	per_cpu_ops_disable_all(ops);
 	return 0;
 }
 
@@ -256,10 +255,11 @@ static inline void update_function_graph_func(void) { }
 static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 {
 	/*
-	 * If this is a dynamic ops or we force list func,
+	 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
 	 * then it needs to call the list anyway.
 	 */
-	if (ops->flags & FTRACE_OPS_FL_DYNAMIC || FTRACE_FORCE_LIST_FUNC)
+	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU |
+			  FTRACE_OPS_FL_RCU) || FTRACE_FORCE_LIST_FUNC)
 		return ftrace_ops_list_func;
 
 	return ftrace_ops_get_func(ops);
@@ -383,26 +383,6 @@ static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 	return 0;
 }
 
-static void add_ftrace_list_ops(struct ftrace_ops **list,
-				struct ftrace_ops *main_ops,
-				struct ftrace_ops *ops)
-{
-	int first = *list == &ftrace_list_end;
-	add_ftrace_ops(list, ops);
-	if (first)
-		add_ftrace_ops(&ftrace_ops_list, main_ops);
-}
-
-static int remove_ftrace_list_ops(struct ftrace_ops **list,
-				  struct ftrace_ops *main_ops,
-				  struct ftrace_ops *ops)
-{
-	int ret = remove_ftrace_ops(list, ops);
-	if (!ret && *list == &ftrace_list_end)
-		ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
-	return ret;
-}
-
 static void ftrace_update_trampoline(struct ftrace_ops *ops);
 
 static int __register_ftrace_function(struct ftrace_ops *ops)
@@ -430,14 +410,12 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	if (!core_kernel_data((unsigned long)ops))
 		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 
-	if (ops->flags & FTRACE_OPS_FL_CONTROL) {
-		if (control_ops_alloc(ops))
+	if (ops->flags & FTRACE_OPS_FL_PER_CPU) {
+		if (per_cpu_ops_alloc(ops))
 			return -ENOMEM;
-		add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
-		/* The control_ops needs the trampoline update */
-		ops = &control_ops;
-	} else
-		add_ftrace_ops(&ftrace_ops_list, ops);
+	}
+
+	add_ftrace_ops(&ftrace_ops_list, ops);
 
 	/* Always save the function, and reset at unregistering */
 	ops->saved_func = ops->func;
@@ -460,11 +438,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
 	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 		return -EBUSY;
 
-	if (ops->flags & FTRACE_OPS_FL_CONTROL) {
-		ret = remove_ftrace_list_ops(&ftrace_control_list,
-					     &control_ops, ops);
-	} else
-		ret = remove_ftrace_ops(&ftrace_ops_list, ops);
+	ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 
 	if (ret < 0)
 		return ret;
@@ -2630,7 +2604,7 @@ void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
 {
 }
 
-static void control_ops_free(struct ftrace_ops *ops)
+static void per_cpu_ops_free(struct ftrace_ops *ops)
 {
 	free_percpu(ops->disabled);
 }
@@ -2731,13 +2705,13 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 
 	if (!command || !ftrace_enabled) {
 		/*
-		 * If these are control ops, they still need their
+		 * If these are per_cpu ops, they still need their
 		 * per_cpu field freed. Since, function tracing is
 		 * not currently active, we can just free them
 		 * without synchronizing all CPUs.
 		 */
-		if (ops->flags & FTRACE_OPS_FL_CONTROL)
-			control_ops_free(ops);
+		if (ops->flags & FTRACE_OPS_FL_PER_CPU)
+			per_cpu_ops_free(ops);
 		return 0;
 	}
 
@@ -2778,7 +2752,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 	/*
 	 * Dynamic ops may be freed, we must make sure that all
 	 * callers are done before leaving this function.
-	 * The same goes for freeing the per_cpu data of the control
+	 * The same goes for freeing the per_cpu data of the per_cpu
 	 * ops.
 	 *
 	 * Again, normal synchronize_sched() is not good enough.
@@ -2789,13 +2763,13 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command)
 	 * infrastructure to do the synchronization, thus we must do it
 	 * ourselves.
 	 */
-	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_CONTROL)) {
+	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_PER_CPU)) {
 		schedule_on_each_cpu(ftrace_sync);
 
 		arch_ftrace_trampoline_free(ops);
 
-		if (ops->flags & FTRACE_OPS_FL_CONTROL)
-			control_ops_free(ops);
+		if (ops->flags & FTRACE_OPS_FL_PER_CPU)
+			per_cpu_ops_free(ops);
 	}
 
 	return 0;
@@ -5185,44 +5159,6 @@ void ftrace_reset_array_ops(struct trace_array *tr)
 	tr->ops->func = ftrace_stub;
 }
 
-static void
-ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
-			struct ftrace_ops *op, struct pt_regs *regs)
-{
-	if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
-		return;
-
-	/*
-	 * Some of the ops may be dynamically allocated,
-	 * they must be freed after a synchronize_sched().
-	 */
-	preempt_disable_notrace();
-	trace_recursion_set(TRACE_CONTROL_BIT);
-
-	/*
-	 * Control funcs (perf) uses RCU. Only trace if
-	 * RCU is currently active.
-	 */
-	if (!rcu_is_watching())
-		goto out;
-
-	do_for_each_ftrace_op(op, ftrace_control_list) {
-		if (!(op->flags & FTRACE_OPS_FL_STUB) &&
-		    !ftrace_function_local_disabled(op) &&
-		    ftrace_ops_test(op, ip, regs))
-			op->func(ip, parent_ip, op, regs);
-	} while_for_each_ftrace_op(op);
- out:
-	trace_recursion_clear(TRACE_CONTROL_BIT);
-	preempt_enable_notrace();
-}
-
-static struct ftrace_ops control_ops = {
-	.func	= ftrace_ops_control_func,
-	.flags	= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
-	INIT_OPS_HASH(control_ops)
-};
-
 static inline void
 __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 		       struct ftrace_ops *ignored, struct pt_regs *regs)
@@ -5239,8 +5175,22 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 	 * they must be freed after a synchronize_sched().
 	 */
 	preempt_disable_notrace();
+
 	do_for_each_ftrace_op(op, ftrace_ops_list) {
-		if (ftrace_ops_test(op, ip, regs)) {
+		/*
+		 * Check the following for each ops before calling their func:
+		 *  if RCU flag is set, then rcu_is_watching() must be true
+		 *  if PER_CPU is set, then ftrace_function_local_disable()
+		 *                          must be false
+		 *  Otherwise test if the ip matches the ops filter
+		 *
+		 * If any of the above fails then the op->func() is not executed.
+		 */
+		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
+		    (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
+		     !ftrace_function_local_disabled(op)) &&
+		    ftrace_ops_test(op, ip, regs)) {
+		    
 			if (FTRACE_WARN_ON(!op->func)) {
 				pr_warn("op=%p %pS\n", op, op);
 				goto out;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 919d9d07686f..d3980b87bf04 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -467,8 +467,6 @@ enum {
 	TRACE_INTERNAL_IRQ_BIT,
 	TRACE_INTERNAL_SIRQ_BIT,
 
-	TRACE_CONTROL_BIT,
-
 	TRACE_BRANCH_BIT,
 /*
  * Abuse of the trace_recursion.
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index abfc903e741e..2649c85cd162 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -334,7 +334,7 @@ static int perf_ftrace_function_register(struct perf_event *event)
 {
 	struct ftrace_ops *ops = &event->ftrace_ops;
 
-	ops->flags |= FTRACE_OPS_FL_CONTROL;
+	ops->flags |= FTRACE_OPS_FL_PER_CPU | FTRACE_OPS_FL_RCU;
 	ops->func = perf_ftrace_function_call;
 	return register_ftrace_function(ops);
 }
-- 
2.6.2

[for-next][PATCH 04/13] ftrace: Have ftrace_ops_get_func() handle RCU and PER_CPU flags too

[Steven Rostedt]

[-- Attachment #1: 0004-ftrace-Have-ftrace_ops_get_func-handle-RCU-and-PER_C.patch --]
[-- Type: text/plain, Size: 3510 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Jiri Olsa noted that the change to replace the control_ops did not update
the trampoline for when running perf on a single CPU and with CONFIG_PREEMPT
disabled (where dynamic ops, like perf, can use trampolines directly). The
result was that perf function could be called when RCU is not watching as
well as not handle the ftrace_local_disable().

Modify the ftrace_ops_get_func() to also check the RCU and PER_CPU ops flags
and use the recursive function if they are set. The recursive function is
modified to check those flags and execute the appropriate checks if they are
set.

Link: http://lkml.kernel.org/r/20151201134213.GA14155@krava.brq.redhat.com

Reported-by: Jiri Olsa <jolsa@redhat.com>
Patch-fixed-up-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index bc7f4eb6b4b0..e290a30f2d0b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -115,9 +115,6 @@ static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 static struct ftrace_ops global_ops;
 
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
-				   struct ftrace_ops *op, struct pt_regs *regs);
-
 #if ARCH_SUPPORTS_FTRACE_OPS
 static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 				 struct ftrace_ops *op, struct pt_regs *regs);
@@ -5231,20 +5228,29 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
 
 /*
  * If there's only one function registered but it does not support
- * recursion, this function will be called by the mcount trampoline.
- * This function will handle recursion protection.
+ * recursion, needs RCU protection and/or requires per cpu handling, then
+ * this function will be called by the mcount trampoline.
  */
-static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
+static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
 				   struct ftrace_ops *op, struct pt_regs *regs)
 {
 	int bit;
 
+	if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
+		return;
+
 	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
 	if (bit < 0)
 		return;
 
-	op->func(ip, parent_ip, op, regs);
+	preempt_disable_notrace();
 
+	if (!(op->flags & FTRACE_OPS_FL_PER_CPU) ||
+	    !ftrace_function_local_disabled(op)) {
+		op->func(ip, parent_ip, op, regs);
+	}
+
+	preempt_enable_notrace();
 	trace_clear_recursion(bit);
 }
 
@@ -5262,12 +5268,12 @@ static void ftrace_ops_recurs_func(unsigned long ip, unsigned long parent_ip,
 ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
 {
 	/*
-	 * If the func handles its own recursion, call it directly.
-	 * Otherwise call the recursion protected function that
-	 * will call the ftrace ops function.
+	 * If the function does not handle recursion, needs to be RCU safe,
+	 * or does per cpu logic, then we need to call the assist handler.
 	 */
-	if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE))
-		return ftrace_ops_recurs_func;
+	if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
+	    ops->flags & (FTRACE_OPS_FL_RCU | FTRACE_OPS_FL_PER_CPU))
+		return ftrace_ops_assist_func;
 
 	return ops->func;
 }
-- 
2.6.2

[for-next][PATCH 05/13] bpf: Constify bpf_verifier_ops structure

[Steven Rostedt]

[-- Attachment #1: 0005-bpf-Constify-bpf_verifier_ops-structure.patch --]
[-- Type: text/plain, Size: 981 bytes --]

From: Julia Lawall <Julia.Lawall@lip6.fr>

This bpf_verifier_ops structure is never modified, like the other
bpf_verifier_ops structures, so declare it as const.

Done with the help of Coccinelle.

Link: http://lkml.kernel.org/r/1449855359-13724-1-git-send-email-Julia.Lawall@lip6.fr

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/bpf_trace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4228fd3682c3..45dd798bcd37 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -316,7 +316,7 @@ static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type
 	return true;
 }
 
-static struct bpf_verifier_ops kprobe_prog_ops = {
+static const struct bpf_verifier_ops kprobe_prog_ops = {
 	.get_func_proto  = kprobe_prog_func_proto,
 	.is_valid_access = kprobe_prog_is_valid_access,
 };
-- 
2.6.2

[for-next][PATCH 06/13] tracing: Use seq_buf_used() in seq_buf_to_user() instead of len

[Steven Rostedt]

[-- Attachment #1: 0006-tracing-Use-seq_buf_used-in-seq_buf_to_user-instead-.patch --]
[-- Type: text/plain, Size: 1173 bytes --]

From: Jerry Snitselaar <jsnitsel@redhat.com>

commit 5ac48378414d ("tracing: Use trace_seq_used() and seq_buf_used()
instead of len") changed the tracing code to use trace_seq_used() and
seq_buf_used() instead of using the seq_buf len directly to avoid
overflow issues, but missed a spot in seq_buf_to_user() that makes use
of s->len.

Cleaned up the code a bit as well per suggestion of Steve Rostedt.

Link: http://lkml.kernel.org/r/1447703848-2951-1-git-send-email-jsnitsel@redhat.com

Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 lib/seq_buf.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/seq_buf.c b/lib/seq_buf.c
index 5c94e1012a91..cb18469e1f49 100644
--- a/lib/seq_buf.c
+++ b/lib/seq_buf.c
@@ -306,10 +306,12 @@ int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt)
 	if (!cnt)
 		return 0;
 
-	if (s->len <= s->readpos)
+	len = seq_buf_used(s);
+
+	if (len <= s->readpos)
 		return -EBUSY;
 
-	len = seq_buf_used(s) - s->readpos;
+	len -= s->readpos;
 	if (cnt > len)
 		cnt = len;
 	ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
-- 
2.6.2

[for-next][PATCH 07/13] tracing: Introduce TRACE_EVENT_FN_COND macro

[Steven Rostedt]

[-- Attachment #1: 0007-tracing-Introduce-TRACE_EVENT_FN_COND-macro.patch --]
[-- Type: text/plain, Size: 2723 bytes --]

From: Denis Kirjanov <kda@linux-powerpc.org>

TRACE_EVENT_FN can't be used in some circumstances
like invoking trace functions from offlined CPU due
to RCU usage.

This patch adds the TRACE_EVENT_FN_COND macro
to make such trace points conditional.

Link: http://lkml.kernel.org/r/1450124286-4822-1-git-send-email-kda@linux-powerpc.org

Signed-off-by: Denis Kirjanov <kda@linux-powerpc.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/tracepoint.h   | 4 ++++
 include/trace/define_trace.h | 6 ++++++
 include/trace/trace_events.h | 6 ++++++
 3 files changed, 16 insertions(+)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 696a339c592c..45b3fcf7dd3c 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -493,6 +493,10 @@ extern void syscall_unregfunc(void);
 #define TRACE_EVENT_FN(name, proto, args, struct,		\
 		assign, print, reg, unreg)			\
 	DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, struct,		\
+		assign, print, reg, unreg)			\
+	DECLARE_TRACE_CONDITION(name, PARAMS(proto),	\
+			PARAMS(args), PARAMS(cond))
 #define TRACE_EVENT_CONDITION(name, proto, args, cond,		\
 			      struct, assign, print)		\
 	DECLARE_TRACE_CONDITION(name, PARAMS(proto),		\
diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h
index 2d8639ea64d5..6e3945f64102 100644
--- a/include/trace/define_trace.h
+++ b/include/trace/define_trace.h
@@ -40,6 +40,11 @@
 		assign, print, reg, unreg)			\
 	DEFINE_TRACE_FN(name, reg, unreg)
 
+#undef TRACE_EVENT_FN_COND
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, tstruct,		\
+		assign, print, reg, unreg)			\
+	DEFINE_TRACE_FN(name, reg, unreg)
+
 #undef DEFINE_EVENT
 #define DEFINE_EVENT(template, name, proto, args) \
 	DEFINE_TRACE(name)
@@ -93,6 +98,7 @@
 
 #undef TRACE_EVENT
 #undef TRACE_EVENT_FN
+#undef TRACE_EVENT_FN_COND
 #undef TRACE_EVENT_CONDITION
 #undef DECLARE_EVENT_CLASS
 #undef DEFINE_EVENT
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index de996cf61053..170c93bbdbb7 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -123,6 +123,12 @@ TRACE_MAKE_SYSTEM_STR();
 	TRACE_EVENT(name, PARAMS(proto), PARAMS(args),			\
 		PARAMS(tstruct), PARAMS(assign), PARAMS(print))		\
 
+#undef TRACE_EVENT_FN_COND
+#define TRACE_EVENT_FN_COND(name, proto, args, cond, tstruct,	\
+		assign, print, reg, unreg)				\
+	TRACE_EVENT_CONDITION(name, PARAMS(proto), PARAMS(args), PARAMS(cond),		\
+		PARAMS(tstruct), PARAMS(assign), PARAMS(print))		\
+
 #undef TRACE_EVENT_FLAGS
 #define TRACE_EVENT_FLAGS(name, value)					\
 	__TRACE_EVENT_FLAGS(name, value)
-- 
2.6.2

[for-next][PATCH 08/13] ftrace: Join functions ftrace_module_init() and ftrace_init_module()

[Steven Rostedt]

[-- Attachment #1: 0008-ftrace-Join-functions-ftrace_module_init-and-ftrace_.patch --]
[-- Type: text/plain, Size: 1352 bytes --]

From: Abel Vesa <abelvesa@linux.com>

Simple cleanup. No need for two functions here.
The whole work can simply be done inside 'ftrace_module_init'.

Link: http://lkml.kernel.org/r/1449067197-5718-1-git-send-email-abelvesa@linux.com

Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e290a30f2d0b..29fcc2c76583 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4980,19 +4980,16 @@ void ftrace_release_mod(struct module *mod)
 	mutex_unlock(&ftrace_lock);
 }
 
-static void ftrace_init_module(struct module *mod,
-			       unsigned long *start, unsigned long *end)
+void ftrace_module_init(struct module *mod)
 {
+	unsigned long *start = mod->ftrace_callsites;
+	unsigned long *end = mod->ftrace_callsites +
+				mod->num_ftrace_callsites;
+
 	if (ftrace_disabled || start == end)
 		return;
-	ftrace_process_locs(mod, start, end);
-}
 
-void ftrace_module_init(struct module *mod)
-{
-	ftrace_init_module(mod, mod->ftrace_callsites,
-			   mod->ftrace_callsites +
-			   mod->num_ftrace_callsites);
+	ftrace_process_locs(mod, start, end);
 }
 
 static int ftrace_module_notify_exit(struct notifier_block *self,
-- 
2.6.2

[for-next][PATCH 09/13] ftrace: Clean up ftrace_module_init() code

[Steven Rostedt]

[-- Attachment #1: 0009-ftrace-Clean-up-ftrace_module_init-code.patch --]
[-- Type: text/plain, Size: 1094 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The start and end variables were only used when ftrace_module_init() was
split up into multiple functions. No need to keep them around after the
merger.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 29fcc2c76583..0f7ee341f89f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4982,14 +4982,11 @@ void ftrace_release_mod(struct module *mod)
 
 void ftrace_module_init(struct module *mod)
 {
-	unsigned long *start = mod->ftrace_callsites;
-	unsigned long *end = mod->ftrace_callsites +
-				mod->num_ftrace_callsites;
-
-	if (ftrace_disabled || start == end)
+	if (ftrace_disabled || !mod->num_ftrace_callsites)
 		return;
 
-	ftrace_process_locs(mod, start, end);
+	ftrace_process_locs(mod, mod->ftrace_callsites,
+			    mod->ftrace_callsites + mod->num_ftrace_callsites);
 }
 
 static int ftrace_module_notify_exit(struct notifier_block *self,
-- 
2.6.2

[for-next][PATCH 10/13] ia64: ftrace: Fix the comments for ftrace_modify_code()

[Steven Rostedt]

[-- Attachment #1: 0010-ia64-ftrace-Fix-the-comments-for-ftrace_modify_code.patch --]
[-- Type: text/plain, Size: 1987 bytes --]

From: Li Bin <huawei.libin@huawei.com>

There is no need to worry about module and __init text disappearing
case, because that ftrace has a module notifier that is called when
a module is being unloaded and before the text goes away and this
code grabs the ftrace_lock mutex and removes the module functions
from the ftrace list, such that it will no longer do any
modifications to that module's text, the update to make functions
be traced or not is done under the ftrace_lock mutex as well.
And by now, __init section codes should not been modified
by ftrace, because it is black listed in recordmcount.c and
ignored by ftrace.

Link: http://lkml.kernel.org/r/1449214067-12177-2-git-send-email-huawei.libin@huawei.com

Cc: linux-ia64@vger.kernel.org
Acked-by: Tony Luck <tony.luck@intel.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/ia64/kernel/ftrace.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/ia64/kernel/ftrace.c b/arch/ia64/kernel/ftrace.c
index 3b0c2aa07857..cee411e647ca 100644
--- a/arch/ia64/kernel/ftrace.c
+++ b/arch/ia64/kernel/ftrace.c
@@ -97,13 +97,11 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 	unsigned char replaced[MCOUNT_INSN_SIZE];
 
 	/*
-	 * Note: Due to modules and __init, code can
-	 *  disappear and change, we need to protect against faulting
-	 *  as well as code changing. We do this by using the
-	 *  probe_kernel_* functions.
-	 *
-	 * No real locking needed, this code is run through
-	 * kstop_machine, or before SMP starts.
+	 * Note:
+	 * We are paranoid about modifying text, as if a bug was to happen, it
+	 * could cause us to read or write to someplace that could cause harm.
+	 * Carefully read and modify the code with probe_kernel_*(), and make
+	 * sure what we read is what we expected it to be before modifying it.
 	 */
 
 	if (!do_check)
-- 
2.6.2

[for-next][PATCH 11/13] sh: ftrace: Fix the comments for ftrace_modify_code()

[Steven Rostedt]

[-- Attachment #1: 0011-sh-ftrace-Fix-the-comments-for-ftrace_modify_code.patch --]
[-- Type: text/plain, Size: 1969 bytes --]

From: Li Bin <huawei.libin@huawei.com>

There is no need to worry about module and __init text disappearing
case, because that ftrace has a module notifier that is called when
a module is being unloaded and before the text goes away and this
code grabs the ftrace_lock mutex and removes the module functions
from the ftrace list, such that it will no longer do any
modifications to that module's text, the update to make functions
be traced or not is done under the ftrace_lock mutex as well.
And by now, __init section codes should not been modified
by ftrace, because it is black listed in recordmcount.c and
ignored by ftrace.

Link: http://lkml.kernel.org/r/1449367378-29430-5-git-send-email-huawei.libin@huawei.com

Cc: linux-sh@vger.kernel.org
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/sh/kernel/ftrace.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/sh/kernel/ftrace.c b/arch/sh/kernel/ftrace.c
index 079d70e6d74b..38993e09ef03 100644
--- a/arch/sh/kernel/ftrace.c
+++ b/arch/sh/kernel/ftrace.c
@@ -212,13 +212,11 @@ static int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 	unsigned char replaced[MCOUNT_INSN_SIZE];
 
 	/*
-	 * Note: Due to modules and __init, code can
-	 *  disappear and change, we need to protect against faulting
-	 *  as well as code changing. We do this by using the
-	 *  probe_kernel_* functions.
-	 *
-	 * No real locking needed, this code is run through
-	 * kstop_machine, or before SMP starts.
+	 * Note:
+	 * We are paranoid about modifying text, as if a bug was to happen, it
+	 * could cause us to read or write to someplace that could cause harm.
+	 * Carefully read and modify the code with probe_kernel_*(), and make
+	 * sure what we read is what we expected it to be before modifying it.
 	 */
 
 	/* read the text we want to modify */
-- 
2.6.2

[for-next][PATCH 12/13] metag: ftrace: Fix the comments for ftrace_modify_code

[Steven Rostedt]

[-- Attachment #1: 0012-metag-ftrace-Fix-the-comments-for-ftrace_modify_code.patch --]
[-- Type: text/plain, Size: 1953 bytes --]

From: Li Bin <huawei.libin@huawei.com>

There is no need to worry about module and __init text disappearing
case, because that ftrace has a module notifier that is called when
a module is being unloaded and before the text goes away and this
code grabs the ftrace_lock mutex and removes the module functions
from the ftrace list, such that it will no longer do any
modifications to that module's text, the update to make functions
be traced or not is done under the ftrace_lock mutex as well.
And by now, __init section codes should not been modified
by ftrace, because it is black listed in recordmcount.c and
ignored by ftrace.

Link: http://lkml.kernel.org/r/1449367378-29430-3-git-send-email-huawei.libin@huawei.com

Cc: linux-metag@vger.kernel.org
Acked-by: James Hogan <james.hogan@imgtec.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/metag/kernel/ftrace.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/metag/kernel/ftrace.c b/arch/metag/kernel/ftrace.c
index ed1d685157c2..ac8c039b0318 100644
--- a/arch/metag/kernel/ftrace.c
+++ b/arch/metag/kernel/ftrace.c
@@ -54,12 +54,11 @@ static int ftrace_modify_code(unsigned long pc, unsigned char *old_code,
 	unsigned char replaced[MCOUNT_INSN_SIZE];
 
 	/*
-	 * Note: Due to modules and __init, code can
-	 *  disappear and change, we need to protect against faulting
-	 *  as well as code changing.
-	 *
-	 * No real locking needed, this code is run through
-	 * kstop_machine.
+	 * Note:
+	 * We are paranoid about modifying text, as if a bug was to happen, it
+	 * could cause us to read or write to someplace that could cause harm.
+	 * Carefully read and modify the code with probe_kernel_*(), and make
+	 * sure what we read is what we expected it to be before modifying it.
 	 */
 
 	/* read the text we want to modify */
-- 
2.6.2

[for-next][PATCH 13/13] tracing: Fix comment to use tracing_on over tracing_enable

[Steven Rostedt]

[-- Attachment #1: 0013-tracing-Fix-comment-to-use-tracing_on-over-tracing_e.patch --]
[-- Type: text/plain, Size: 1284 bytes --]

From: Chuyu Hu <chuhu@redhat.com>

The file tracing_enable is obsolete and does not exist anymore. Replace
the comment that references it with the proper tracing_on file.

Link: http://lkml.kernel.org/r/1450787141-45544-1-git-send-email-chuhu@redhat.com

Signed-off-by: Chuyu Hu <chuhu@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d3980b87bf04..8414fa40bf27 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -363,8 +363,8 @@ struct trace_option_dentry {
  * @name: the name chosen to select it on the available_tracers file
  * @init: called when one switches to this tracer (echo name > current_tracer)
  * @reset: called when one switches to another tracer
- * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
- * @stop: called when tracing is paused (echo 0 > tracing_enabled)
+ * @start: called when tracing is unpaused (echo 1 > tracing_on)
+ * @stop: called when tracing is paused (echo 0 > tracing_on)
  * @update_thresh: called when tracing_thresh is updated
  * @open: called when the trace file is opened
  * @pipe_open: called when the trace_pipe file is opened
-- 
2.6.2