[for-next][PATCH 00/13] tracing: Updates for 5.13

[for-next][PATCH 00/13] tracing: Updates for 5.13

[Steven Rostedt]

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

Head SHA1: 9a6944fee68e25084130386c608c5ac8db487581

Cao jin (1):
      bootconfig: Update prototype of setup_boot_config()

Colin Ian King (1):
      ftrace: Fix spelling mistake "disabed" -> "disabled"

Steven Rostedt (VMware) (10):
      ring-buffer: Separate out internal use of ring_buffer_event_time_stamp()
      ring-buffer: Add a event_stamp to cpu_buffer for each level of nesting
      tracing: Pass buffer of event to trigger operations
      ring-buffer: Allow ring_buffer_event_time_stamp() to return time stamp of all events
      tracing: Use a no_filter_buffering_ref to stop using the filter buffer
      ring-buffer: Add verifier for using ring_buffer_event_time_stamp()
      tracing: Add tracing_event_time_stamp() API
      tracing: Add check of trace event print fmts for dereferencing pointers
      seq_buf: Add seq_buf_terminate() API
      tracing: Add a verifier to check string pointers for trace events

Xu Wang (1):
      tools/latency-collector: Remove unneeded semicolon

----
 arch/csky/kernel/probes/ftrace.c          |   2 +-
 arch/riscv/kernel/probes/ftrace.c         |   2 +-
 arch/x86/kernel/kprobes/ftrace.c          |   2 +-
 include/linux/ring_buffer.h               |   3 +-
 include/linux/seq_buf.h                   |  25 ++++
 include/linux/trace_events.h              |   5 +-
 init/main.c                               |   6 +-
 kernel/trace/ring_buffer.c                | 138 ++++++++++++++---
 kernel/trace/trace.c                      | 238 +++++++++++++++++++++++++++---
 kernel/trace/trace.h                      |  12 +-
 kernel/trace/trace_events.c               | 210 ++++++++++++++++++++++++++
 kernel/trace/trace_events_hist.c          | 100 ++++++++-----
 kernel/trace/trace_events_trigger.c       |  45 +++---
 kernel/trace/trace_output.c               |   2 +-
 kernel/trace/trace_printk.c               |  11 ++
 tools/tracing/latency/latency-collector.c |   4 +-
 16 files changed, 697 insertions(+), 108 deletions(-)

[for-next][PATCH 01/13] ring-buffer: Separate out internal use of ring_buffer_event_time_stamp()

[Steven Rostedt]

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

The exported use of ring_buffer_event_time_stamp() is going to become
different than how it is used internally. Move the internal logic out into a
static function called rb_event_time_stamp(), and have the internal callers
call that instead.

Link: https://lkml.kernel.org/r/20210316164113.257790481@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 41 +++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 68744c51517e..941ac2021b97 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -287,6 +287,17 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data);
 #define TS_MASK		((1ULL << TS_SHIFT) - 1)
 #define TS_DELTA_TEST	(~TS_MASK)
 
+static u64 rb_event_time_stamp(struct ring_buffer_event *event)
+{
+	u64 ts;
+
+	ts = event->array[0];
+	ts <<= TS_SHIFT;
+	ts += event->time_delta;
+
+	return ts;
+}
+
 /**
  * ring_buffer_event_time_stamp - return the event's extended timestamp
  * @event: the event to get the timestamp of
@@ -299,13 +310,7 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data);
  */
 u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event)
 {
-	u64 ts;
-
-	ts = event->array[0];
-	ts <<= TS_SHIFT;
-	ts += event->time_delta;
-
-	return ts;
+	return rb_event_time_stamp(event);
 }
 
 /* Flag when events were overwritten */
@@ -2766,7 +2771,7 @@ static u64 rb_time_delta(struct ring_buffer_event *event)
 		return 0;
 
 	case RINGBUF_TYPE_TIME_EXTEND:
-		return ring_buffer_event_time_stamp(event);
+		return rb_event_time_stamp(event);
 
 	case RINGBUF_TYPE_TIME_STAMP:
 		return 0;
@@ -3212,13 +3217,13 @@ static void dump_buffer_page(struct buffer_data_page *bpage,
 		switch (event->type_len) {
 
 		case RINGBUF_TYPE_TIME_EXTEND:
-			delta = ring_buffer_event_time_stamp(event);
+			delta = rb_event_time_stamp(event);
 			ts += delta;
 			pr_warn("  [%lld] delta:%lld TIME EXTEND\n", ts, delta);
 			break;
 
 		case RINGBUF_TYPE_TIME_STAMP:
-			delta = ring_buffer_event_time_stamp(event);
+			delta = rb_event_time_stamp(event);
 			ts = delta;
 			pr_warn("  [%lld] absolute:%lld TIME STAMP\n", ts, delta);
 			break;
@@ -3289,12 +3294,12 @@ static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer,
 		switch (event->type_len) {
 
 		case RINGBUF_TYPE_TIME_EXTEND:
-			delta = ring_buffer_event_time_stamp(event);
+			delta = rb_event_time_stamp(event);
 			ts += delta;
 			break;
 
 		case RINGBUF_TYPE_TIME_STAMP:
-			delta = ring_buffer_event_time_stamp(event);
+			delta = rb_event_time_stamp(event);
 			ts = delta;
 			break;
 
@@ -4256,12 +4261,12 @@ rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer,
 		return;
 
 	case RINGBUF_TYPE_TIME_EXTEND:
-		delta = ring_buffer_event_time_stamp(event);
+		delta = rb_event_time_stamp(event);
 		cpu_buffer->read_stamp += delta;
 		return;
 
 	case RINGBUF_TYPE_TIME_STAMP:
-		delta = ring_buffer_event_time_stamp(event);
+		delta = rb_event_time_stamp(event);
 		cpu_buffer->read_stamp = delta;
 		return;
 
@@ -4286,12 +4291,12 @@ rb_update_iter_read_stamp(struct ring_buffer_iter *iter,
 		return;
 
 	case RINGBUF_TYPE_TIME_EXTEND:
-		delta = ring_buffer_event_time_stamp(event);
+		delta = rb_event_time_stamp(event);
 		iter->read_stamp += delta;
 		return;
 
 	case RINGBUF_TYPE_TIME_STAMP:
-		delta = ring_buffer_event_time_stamp(event);
+		delta = rb_event_time_stamp(event);
 		iter->read_stamp = delta;
 		return;
 
@@ -4544,7 +4549,7 @@ rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts,
 
 	case RINGBUF_TYPE_TIME_STAMP:
 		if (ts) {
-			*ts = ring_buffer_event_time_stamp(event);
+			*ts = rb_event_time_stamp(event);
 			ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
 							 cpu_buffer->cpu, ts);
 		}
@@ -4635,7 +4640,7 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 
 	case RINGBUF_TYPE_TIME_STAMP:
 		if (ts) {
-			*ts = ring_buffer_event_time_stamp(event);
+			*ts = rb_event_time_stamp(event);
 			ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
 							 cpu_buffer->cpu, ts);
 		}
-- 
2.30.1

[for-next][PATCH 02/13] ring-buffer: Add a event_stamp to cpu_buffer for each level of nesting

[Steven Rostedt]

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

Add a place to save the current event time stamp for each level of nesting.
This will be used to retrieve the time stamp of the current event before it
is committed.

Link: https://lkml.kernel.org/r/20210316164113.399089673@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 941ac2021b97..470d97169081 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -492,6 +492,8 @@ struct rb_time_struct {
 #endif
 typedef struct rb_time_struct rb_time_t;
 
+#define MAX_NEST	5
+
 /*
  * head_page == tail_page && head == tail then buffer is empty.
  */
@@ -529,6 +531,7 @@ struct ring_buffer_per_cpu {
 	unsigned long			read_bytes;
 	rb_time_t			write_stamp;
 	rb_time_t			before_stamp;
+	u64				event_stamp[MAX_NEST];
 	u64				read_stamp;
 	/* ring buffer pages to update, > 0 to add, < 0 to remove */
 	long				nr_pages_to_update;
@@ -2715,6 +2718,10 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
 {
 	unsigned length = info->length;
 	u64 delta = info->delta;
+	unsigned int nest = local_read(&cpu_buffer->committing) - 1;
+
+	if (nest < MAX_NEST)
+		cpu_buffer->event_stamp[nest] = info->ts;
 
 	/*
 	 * If we need to add a timestamp, then we
@@ -3456,7 +3463,6 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 				    info->after, ts)) {
 			/* Nothing came after this event between C and E */
 			info->delta = ts - info->after;
-			info->ts = ts;
 		} else {
 			/*
 			 * Interrupted between C and E:
@@ -3468,6 +3474,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
 			 */
 			info->delta = 0;
 		}
+		info->ts = ts;
 		info->add_timestamp &= ~RB_ADD_STAMP_FORCE;
 	}
 
@@ -5026,6 +5033,8 @@ rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
 	rb_time_set(&cpu_buffer->write_stamp, 0);
 	rb_time_set(&cpu_buffer->before_stamp, 0);
 
+	memset(cpu_buffer->event_stamp, 0, sizeof(cpu_buffer->event_stamp));
+
 	cpu_buffer->lost_events = 0;
 	cpu_buffer->last_overrun = 0;
 
-- 
2.30.1

[for-next][PATCH 03/13] tracing: Pass buffer of event to trigger operations

[Steven Rostedt]

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

The ring_buffer_event_time_stamp() is going to be updated to extract the
time stamp for the event without needing it to be set to have absolute
values for all events. But to do so, it needs the buffer that the event is
on as the buffer saves information for the event before it is committed to
the buffer.

If the trace buffer is disabled, a temporary buffer is used, and there's
no access to this buffer from the current histogram triggers, even though
it is passed to the trace event code.

Pass the buffer that the event is on all the way down to the histogram
triggers.

Link: https://lkml.kernel.org/r/20210316164113.542448131@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/trace_events.h        |  5 +-
 kernel/trace/trace.c                |  2 +-
 kernel/trace/trace.h                |  4 +-
 kernel/trace/trace_events_hist.c    | 92 +++++++++++++++++++----------
 kernel/trace/trace_events_trigger.c | 45 ++++++++------
 5 files changed, 95 insertions(+), 53 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 28e7af1406f2..8cba64ce23a4 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -640,7 +640,8 @@ enum event_trigger_type {
 extern int filter_match_preds(struct event_filter *filter, void *rec);
 
 extern enum event_trigger_type
-event_triggers_call(struct trace_event_file *file, void *rec,
+event_triggers_call(struct trace_event_file *file,
+		    struct trace_buffer *buffer, void *rec,
 		    struct ring_buffer_event *event);
 extern void
 event_triggers_post_call(struct trace_event_file *file,
@@ -664,7 +665,7 @@ trace_trigger_soft_disabled(struct trace_event_file *file)
 
 	if (!(eflags & EVENT_FILE_FL_TRIGGER_COND)) {
 		if (eflags & EVENT_FILE_FL_TRIGGER_MODE)
-			event_triggers_call(file, NULL, NULL);
+			event_triggers_call(file, NULL, NULL, NULL);
 		if (eflags & EVENT_FILE_FL_SOFT_DISABLED)
 			return true;
 		if (eflags & EVENT_FILE_FL_PID_FILTER)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eccb4e1187cc..f979220238a5 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6763,7 +6763,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
 		/* do not add \n before testing triggers, but add \0 */
 		entry->buf[cnt] = '\0';
-		tt = event_triggers_call(tr->trace_marker_file, entry, event);
+		tt = event_triggers_call(tr->trace_marker_file, buffer, entry, event);
 	}
 
 	if (entry->buf[cnt - 1] != '\n') {
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a6446c03cfbc..798773178d7e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1329,7 +1329,7 @@ __event_trigger_test_discard(struct trace_event_file *file,
 	unsigned long eflags = file->flags;
 
 	if (eflags & EVENT_FILE_FL_TRIGGER_COND)
-		*tt = event_triggers_call(file, entry, event);
+		*tt = event_triggers_call(file, buffer, entry, event);
 
 	if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) ||
 	    (unlikely(file->flags & EVENT_FILE_FL_FILTERED) &&
@@ -1626,7 +1626,7 @@ extern int register_trigger_hist_enable_disable_cmds(void);
  */
 struct event_trigger_ops {
 	void			(*func)(struct event_trigger_data *data,
-					void *rec,
+					struct trace_buffer *buffer, void *rec,
 					struct ring_buffer_event *rbe);
 	int			(*init)(struct event_trigger_ops *ops,
 					struct event_trigger_data *data);
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 39ebe1826fc3..6978aa3ee4c5 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -81,6 +81,7 @@ struct hist_field;
 
 typedef u64 (*hist_field_fn_t) (struct hist_field *field,
 				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
 				struct ring_buffer_event *rbe,
 				void *event);
 
@@ -153,6 +154,7 @@ struct hist_field {
 
 static u64 hist_field_none(struct hist_field *field,
 			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
 			   struct ring_buffer_event *rbe,
 			   void *event)
 {
@@ -161,6 +163,7 @@ static u64 hist_field_none(struct hist_field *field,
 
 static u64 hist_field_counter(struct hist_field *field,
 			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
 			      struct ring_buffer_event *rbe,
 			      void *event)
 {
@@ -169,6 +172,7 @@ static u64 hist_field_counter(struct hist_field *field,
 
 static u64 hist_field_string(struct hist_field *hist_field,
 			     struct tracing_map_elt *elt,
+			     struct trace_buffer *buffer,
 			     struct ring_buffer_event *rbe,
 			     void *event)
 {
@@ -179,6 +183,7 @@ static u64 hist_field_string(struct hist_field *hist_field,
 
 static u64 hist_field_dynstring(struct hist_field *hist_field,
 				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
 				struct ring_buffer_event *rbe,
 				void *event)
 {
@@ -191,6 +196,7 @@ static u64 hist_field_dynstring(struct hist_field *hist_field,
 
 static u64 hist_field_pstring(struct hist_field *hist_field,
 			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
 			      struct ring_buffer_event *rbe,
 			      void *event)
 {
@@ -201,52 +207,56 @@ static u64 hist_field_pstring(struct hist_field *hist_field,
 
 static u64 hist_field_log2(struct hist_field *hist_field,
 			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
 			   struct ring_buffer_event *rbe,
 			   void *event)
 {
 	struct hist_field *operand = hist_field->operands[0];
 
-	u64 val = operand->fn(operand, elt, rbe, event);
+	u64 val = operand->fn(operand, elt, buffer, rbe, event);
 
 	return (u64) ilog2(roundup_pow_of_two(val));
 }
 
 static u64 hist_field_plus(struct hist_field *hist_field,
 			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer,
 			   struct ring_buffer_event *rbe,
 			   void *event)
 {
 	struct hist_field *operand1 = hist_field->operands[0];
 	struct hist_field *operand2 = hist_field->operands[1];
 
-	u64 val1 = operand1->fn(operand1, elt, rbe, event);
-	u64 val2 = operand2->fn(operand2, elt, rbe, event);
+	u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
+	u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 
 	return val1 + val2;
 }
 
 static u64 hist_field_minus(struct hist_field *hist_field,
 			    struct tracing_map_elt *elt,
+			    struct trace_buffer *buffer,
 			    struct ring_buffer_event *rbe,
 			    void *event)
 {
 	struct hist_field *operand1 = hist_field->operands[0];
 	struct hist_field *operand2 = hist_field->operands[1];
 
-	u64 val1 = operand1->fn(operand1, elt, rbe, event);
-	u64 val2 = operand2->fn(operand2, elt, rbe, event);
+	u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
+	u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
 
 	return val1 - val2;
 }
 
 static u64 hist_field_unary_minus(struct hist_field *hist_field,
 				  struct tracing_map_elt *elt,
+				  struct trace_buffer *buffer,
 				  struct ring_buffer_event *rbe,
 				  void *event)
 {
 	struct hist_field *operand = hist_field->operands[0];
 
-	s64 sval = (s64)operand->fn(operand, elt, rbe, event);
+	s64 sval = (s64)operand->fn(operand, elt, buffer, rbe, event);
 	u64 val = (u64)-sval;
 
 	return val;
@@ -255,6 +265,7 @@ static u64 hist_field_unary_minus(struct hist_field *hist_field,
 #define DEFINE_HIST_FIELD_FN(type)					\
 	static u64 hist_field_##type(struct hist_field *hist_field,	\
 				     struct tracing_map_elt *elt,	\
+				     struct trace_buffer *buffer,	\
 				     struct ring_buffer_event *rbe,	\
 				     void *event)			\
 {									\
@@ -380,7 +391,8 @@ struct hist_trigger_data {
 struct action_data;
 
 typedef void (*action_fn_t) (struct hist_trigger_data *hist_data,
-			     struct tracing_map_elt *elt, void *rec,
+			     struct tracing_map_elt *elt,
+			     struct trace_buffer *buffer, void *rec,
 			     struct ring_buffer_event *rbe, void *key,
 			     struct action_data *data, u64 *var_ref_vals);
 
@@ -608,7 +620,8 @@ static inline void trace_synth(struct synth_event *event, u64 *var_ref_vals,
 }
 
 static void action_trace(struct hist_trigger_data *hist_data,
-			 struct tracing_map_elt *elt, void *rec,
+			 struct tracing_map_elt *elt,
+			 struct trace_buffer *buffer, void *rec,
 			 struct ring_buffer_event *rbe, void *key,
 			 struct action_data *data, u64 *var_ref_vals)
 {
@@ -624,6 +637,7 @@ struct hist_var_data {
 
 static u64 hist_field_timestamp(struct hist_field *hist_field,
 				struct tracing_map_elt *elt,
+				struct trace_buffer *buffer,
 				struct ring_buffer_event *rbe,
 				void *event)
 {
@@ -640,6 +654,7 @@ static u64 hist_field_timestamp(struct hist_field *hist_field,
 
 static u64 hist_field_cpu(struct hist_field *hist_field,
 			  struct tracing_map_elt *elt,
+			  struct trace_buffer *buffer,
 			  struct ring_buffer_event *rbe,
 			  void *event)
 {
@@ -1020,6 +1035,7 @@ static struct hist_field *find_event_var(struct hist_trigger_data *hist_data,
 
 static u64 hist_field_var_ref(struct hist_field *hist_field,
 			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
 			      struct ring_buffer_event *rbe,
 			      void *event)
 {
@@ -2561,6 +2577,7 @@ find_target_event_var(struct hist_trigger_data *hist_data,
 }
 
 static inline void __update_field_vars(struct tracing_map_elt *elt,
+				       struct trace_buffer *buffer,
 				       struct ring_buffer_event *rbe,
 				       void *rec,
 				       struct field_var **field_vars,
@@ -2576,7 +2593,7 @@ static inline void __update_field_vars(struct tracing_map_elt *elt,
 		struct hist_field *var = field_var->var;
 		struct hist_field *val = field_var->val;
 
-		var_val = val->fn(val, elt, rbe, rec);
+		var_val = val->fn(val, elt, buffer, rbe, rec);
 		var_idx = var->var.idx;
 
 		if (val->flags & HIST_FIELD_FL_STRING) {
@@ -2592,19 +2609,21 @@ static inline void __update_field_vars(struct tracing_map_elt *elt,
 
 static void update_field_vars(struct hist_trigger_data *hist_data,
 			      struct tracing_map_elt *elt,
+			      struct trace_buffer *buffer,
 			      struct ring_buffer_event *rbe,
 			      void *rec)
 {
-	__update_field_vars(elt, rbe, rec, hist_data->field_vars,
+	__update_field_vars(elt, buffer, rbe, rec, hist_data->field_vars,
 			    hist_data->n_field_vars, 0);
 }
 
 static void save_track_data_vars(struct hist_trigger_data *hist_data,
-				 struct tracing_map_elt *elt, void *rec,
+				 struct tracing_map_elt *elt,
+				 struct trace_buffer *buffer,  void *rec,
 				 struct ring_buffer_event *rbe, void *key,
 				 struct action_data *data, u64 *var_ref_vals)
 {
-	__update_field_vars(elt, rbe, rec, hist_data->save_vars,
+	__update_field_vars(elt, buffer, rbe, rec, hist_data->save_vars,
 			    hist_data->n_save_vars, hist_data->n_field_var_str);
 }
 
@@ -2780,12 +2799,14 @@ static void save_track_val(struct hist_trigger_data *hist_data,
 }
 
 static void save_track_data(struct hist_trigger_data *hist_data,
-			    struct tracing_map_elt *elt, void *rec,
+			    struct tracing_map_elt *elt,
+			    struct trace_buffer *buffer, void *rec,
 			    struct ring_buffer_event *rbe, void *key,
 			    struct action_data *data, u64 *var_ref_vals)
 {
 	if (data->track_data.save_data)
-		data->track_data.save_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
+		data->track_data.save_data(hist_data, elt, buffer, rec, rbe,
+					   key, data, var_ref_vals);
 }
 
 static bool check_track_val(struct tracing_map_elt *elt,
@@ -2836,7 +2857,8 @@ static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
 }
 
 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
-				     struct tracing_map_elt *elt, void *rec,
+				     struct tracing_map_elt *elt,
+				     struct trace_buffer *buffer, void *rec,
 				     struct ring_buffer_event *rbe, void *key,
 				     struct action_data *data,
 				     u64 *var_ref_vals)
@@ -2905,7 +2927,8 @@ static bool cond_snapshot_update(struct trace_array *tr, void *cond_data)
 	return false;
 }
 static void save_track_data_snapshot(struct hist_trigger_data *hist_data,
-				     struct tracing_map_elt *elt, void *rec,
+				     struct tracing_map_elt *elt,
+				     struct trace_buffer *buffer, void *rec,
 				     struct ring_buffer_event *rbe, void *key,
 				     struct action_data *data,
 				     u64 *var_ref_vals) {}
@@ -2947,7 +2970,8 @@ static void track_data_print(struct seq_file *m,
 }
 
 static void ontrack_action(struct hist_trigger_data *hist_data,
-			   struct tracing_map_elt *elt, void *rec,
+			   struct tracing_map_elt *elt,
+			   struct trace_buffer *buffer, void *rec,
 			   struct ring_buffer_event *rbe, void *key,
 			   struct action_data *data, u64 *var_ref_vals)
 {
@@ -2955,7 +2979,8 @@ static void ontrack_action(struct hist_trigger_data *hist_data,
 
 	if (check_track_val(elt, data, var_val)) {
 		save_track_val(hist_data, elt, data, var_val);
-		save_track_data(hist_data, elt, rec, rbe, key, data, var_ref_vals);
+		save_track_data(hist_data, elt, buffer, rec, rbe,
+				key, data, var_ref_vals);
 	}
 }
 
@@ -4400,7 +4425,8 @@ create_hist_data(unsigned int map_bits,
 }
 
 static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
-				    struct tracing_map_elt *elt, void *rec,
+				    struct tracing_map_elt *elt,
+				    struct trace_buffer *buffer, void *rec,
 				    struct ring_buffer_event *rbe,
 				    u64 *var_ref_vals)
 {
@@ -4414,7 +4440,7 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
 
 	for_each_hist_val_field(i, hist_data) {
 		hist_field = hist_data->fields[i];
-		hist_val = hist_field->fn(hist_field, elt, rbe, rec);
+		hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
 			var_idx = hist_field->var.idx;
 
@@ -4442,13 +4468,13 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
 	for_each_hist_key_field(i, hist_data) {
 		hist_field = hist_data->fields[i];
 		if (hist_field->flags & HIST_FIELD_FL_VAR) {
-			hist_val = hist_field->fn(hist_field, elt, rbe, rec);
+			hist_val = hist_field->fn(hist_field, elt, buffer, rbe, rec);
 			var_idx = hist_field->var.idx;
 			tracing_map_set_var(elt, var_idx, hist_val);
 		}
 	}
 
-	update_field_vars(hist_data, elt, rbe, rec);
+	update_field_vars(hist_data, elt, buffer, rbe, rec);
 }
 
 static inline void add_to_key(char *compound_key, void *key,
@@ -4478,7 +4504,8 @@ static inline void add_to_key(char *compound_key, void *key,
 
 static void
 hist_trigger_actions(struct hist_trigger_data *hist_data,
-		     struct tracing_map_elt *elt, void *rec,
+		     struct tracing_map_elt *elt,
+		     struct trace_buffer *buffer, void *rec,
 		     struct ring_buffer_event *rbe, void *key,
 		     u64 *var_ref_vals)
 {
@@ -4487,11 +4514,12 @@ hist_trigger_actions(struct hist_trigger_data *hist_data,
 
 	for (i = 0; i < hist_data->n_actions; i++) {
 		data = hist_data->actions[i];
-		data->fn(hist_data, elt, rec, rbe, key, data, var_ref_vals);
+		data->fn(hist_data, elt, buffer, rec, rbe, key, data, var_ref_vals);
 	}
 }
 
-static void event_hist_trigger(struct event_trigger_data *data, void *rec,
+static void event_hist_trigger(struct event_trigger_data *data,
+			       struct trace_buffer *buffer, void *rec,
 			       struct ring_buffer_event *rbe)
 {
 	struct hist_trigger_data *hist_data = data->private_data;
@@ -4516,7 +4544,7 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec,
 					 HIST_STACKTRACE_SKIP);
 			key = entries;
 		} else {
-			field_contents = key_field->fn(key_field, elt, rbe, rec);
+			field_contents = key_field->fn(key_field, elt, buffer, rbe, rec);
 			if (key_field->flags & HIST_FIELD_FL_STRING) {
 				key = (void *)(unsigned long)field_contents;
 				use_compound_key = true;
@@ -4539,10 +4567,10 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec,
 	if (!elt)
 		return;
 
-	hist_trigger_elt_update(hist_data, elt, rec, rbe, var_ref_vals);
+	hist_trigger_elt_update(hist_data, elt, buffer, rec, rbe, var_ref_vals);
 
 	if (resolve_var_refs(hist_data, key, var_ref_vals, true))
-		hist_trigger_actions(hist_data, elt, rec, rbe, key, var_ref_vals);
+		hist_trigger_actions(hist_data, elt, buffer, rec, rbe, key, var_ref_vals);
 }
 
 static void hist_trigger_stacktrace_print(struct seq_file *m,
@@ -5812,7 +5840,8 @@ __init int register_trigger_hist_cmd(void)
 }
 
 static void
-hist_enable_trigger(struct event_trigger_data *data, void *rec,
+hist_enable_trigger(struct event_trigger_data *data,
+		    struct trace_buffer *buffer,  void *rec,
 		    struct ring_buffer_event *event)
 {
 	struct enable_trigger_data *enable_data = data->private_data;
@@ -5830,7 +5859,8 @@ hist_enable_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-hist_enable_count_trigger(struct event_trigger_data *data, void *rec,
+hist_enable_count_trigger(struct event_trigger_data *data,
+			  struct trace_buffer *buffer,  void *rec,
 			  struct ring_buffer_event *event)
 {
 	if (!data->count)
@@ -5839,7 +5869,7 @@ hist_enable_count_trigger(struct event_trigger_data *data, void *rec,
 	if (data->count != -1)
 		(data->count)--;
 
-	hist_enable_trigger(data, rec, event);
+	hist_enable_trigger(data, buffer, rec, event);
 }
 
 static struct event_trigger_ops hist_enable_trigger_ops = {
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index f725802160c0..b8bfa8505b7b 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -53,7 +53,8 @@ void trigger_data_free(struct event_trigger_data *data)
  * any trigger that should be deferred, ETT_NONE if nothing to defer.
  */
 enum event_trigger_type
-event_triggers_call(struct trace_event_file *file, void *rec,
+event_triggers_call(struct trace_event_file *file,
+		    struct trace_buffer *buffer, void *rec,
 		    struct ring_buffer_event *event)
 {
 	struct event_trigger_data *data;
@@ -67,7 +68,7 @@ event_triggers_call(struct trace_event_file *file, void *rec,
 		if (data->paused)
 			continue;
 		if (!rec) {
-			data->ops->func(data, rec, event);
+			data->ops->func(data, buffer, rec, event);
 			continue;
 		}
 		filter = rcu_dereference_sched(data->filter);
@@ -77,7 +78,7 @@ event_triggers_call(struct trace_event_file *file, void *rec,
 			tt |= data->cmd_ops->trigger_type;
 			continue;
 		}
-		data->ops->func(data, rec, event);
+		data->ops->func(data, buffer, rec, event);
 	}
 	return tt;
 }
@@ -105,7 +106,7 @@ event_triggers_post_call(struct trace_event_file *file,
 		if (data->paused)
 			continue;
 		if (data->cmd_ops->trigger_type & tt)
-			data->ops->func(data, NULL, NULL);
+			data->ops->func(data, NULL, NULL, NULL);
 	}
 }
 EXPORT_SYMBOL_GPL(event_triggers_post_call);
@@ -937,7 +938,8 @@ get_named_trigger_data(struct event_trigger_data *data)
 }
 
 static void
-traceon_trigger(struct event_trigger_data *data, void *rec,
+traceon_trigger(struct event_trigger_data *data,
+		struct trace_buffer *buffer, void *rec,
 		struct ring_buffer_event *event)
 {
 	if (tracing_is_on())
@@ -947,7 +949,8 @@ traceon_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-traceon_count_trigger(struct event_trigger_data *data, void *rec,
+traceon_count_trigger(struct event_trigger_data *data,
+		      struct trace_buffer *buffer, void *rec,
 		      struct ring_buffer_event *event)
 {
 	if (tracing_is_on())
@@ -963,7 +966,8 @@ traceon_count_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-traceoff_trigger(struct event_trigger_data *data, void *rec,
+traceoff_trigger(struct event_trigger_data *data,
+		 struct trace_buffer *buffer, void *rec,
 		 struct ring_buffer_event *event)
 {
 	if (!tracing_is_on())
@@ -973,7 +977,8 @@ traceoff_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-traceoff_count_trigger(struct event_trigger_data *data, void *rec,
+traceoff_count_trigger(struct event_trigger_data *data,
+		       struct trace_buffer *buffer, void *rec,
 		       struct ring_buffer_event *event)
 {
 	if (!tracing_is_on())
@@ -1071,7 +1076,8 @@ static struct event_command trigger_traceoff_cmd = {
 
 #ifdef CONFIG_TRACER_SNAPSHOT
 static void
-snapshot_trigger(struct event_trigger_data *data, void *rec,
+snapshot_trigger(struct event_trigger_data *data,
+		 struct trace_buffer *buffer, void *rec,
 		 struct ring_buffer_event *event)
 {
 	struct trace_event_file *file = data->private_data;
@@ -1083,7 +1089,8 @@ snapshot_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-snapshot_count_trigger(struct event_trigger_data *data, void *rec,
+snapshot_count_trigger(struct event_trigger_data *data,
+		       struct trace_buffer *buffer, void *rec,
 		       struct ring_buffer_event *event)
 {
 	if (!data->count)
@@ -1092,7 +1099,7 @@ snapshot_count_trigger(struct event_trigger_data *data, void *rec,
 	if (data->count != -1)
 		(data->count)--;
 
-	snapshot_trigger(data, rec, event);
+	snapshot_trigger(data, buffer, rec, event);
 }
 
 static int
@@ -1176,14 +1183,16 @@ static __init int register_trigger_snapshot_cmd(void) { return 0; }
 #endif
 
 static void
-stacktrace_trigger(struct event_trigger_data *data, void *rec,
+stacktrace_trigger(struct event_trigger_data *data,
+		   struct trace_buffer *buffer,  void *rec,
 		   struct ring_buffer_event *event)
 {
 	trace_dump_stack(STACK_SKIP);
 }
 
 static void
-stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
+stacktrace_count_trigger(struct event_trigger_data *data,
+			 struct trace_buffer *buffer, void *rec,
 			 struct ring_buffer_event *event)
 {
 	if (!data->count)
@@ -1192,7 +1201,7 @@ stacktrace_count_trigger(struct event_trigger_data *data, void *rec,
 	if (data->count != -1)
 		(data->count)--;
 
-	stacktrace_trigger(data, rec, event);
+	stacktrace_trigger(data, buffer, rec, event);
 }
 
 static int
@@ -1254,7 +1263,8 @@ static __init void unregister_trigger_traceon_traceoff_cmds(void)
 }
 
 static void
-event_enable_trigger(struct event_trigger_data *data, void *rec,
+event_enable_trigger(struct event_trigger_data *data,
+		     struct trace_buffer *buffer,  void *rec,
 		     struct ring_buffer_event *event)
 {
 	struct enable_trigger_data *enable_data = data->private_data;
@@ -1266,7 +1276,8 @@ event_enable_trigger(struct event_trigger_data *data, void *rec,
 }
 
 static void
-event_enable_count_trigger(struct event_trigger_data *data, void *rec,
+event_enable_count_trigger(struct event_trigger_data *data,
+			   struct trace_buffer *buffer,  void *rec,
 			   struct ring_buffer_event *event)
 {
 	struct enable_trigger_data *enable_data = data->private_data;
@@ -1281,7 +1292,7 @@ event_enable_count_trigger(struct event_trigger_data *data, void *rec,
 	if (data->count != -1)
 		(data->count)--;
 
-	event_enable_trigger(data, rec, event);
+	event_enable_trigger(data, buffer, rec, event);
 }
 
 int event_enable_trigger_print(struct seq_file *m,
-- 
2.30.1

[for-next][PATCH 04/13] ring-buffer: Allow ring_buffer_event_time_stamp() to return time stamp of all events

[Steven Rostedt]

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

Currently, ring_buffer_event_time_stamp() only returns an accurate time
stamp of the event if it has an absolute extended time stamp attached to
it. To make it more robust, use the event_stamp() in case the event does
not have an absolute value attached to it.

This will allow ring_buffer_event_time_stamp() to be used in more cases
than just histograms, and it will also allow histograms to not require
including absolute values all the time.

Link: https://lkml.kernel.org/r/20210316164113.704830885@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/ring_buffer.h      |  3 +-
 kernel/trace/ring_buffer.c       | 60 ++++++++++++++++++++++++--------
 kernel/trace/trace_events_hist.c |  2 +-
 3 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 136ea0997e6d..057b7ed4fe24 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -61,7 +61,8 @@ enum ring_buffer_type {
 
 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
 void *ring_buffer_event_data(struct ring_buffer_event *event);
-u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event);
+u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
+				 struct ring_buffer_event *event);
 
 /*
  * ring_buffer_discard_commit will remove an event that has not
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 470d97169081..8fa2a84f714f 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -298,21 +298,6 @@ static u64 rb_event_time_stamp(struct ring_buffer_event *event)
 	return ts;
 }
 
-/**
- * ring_buffer_event_time_stamp - return the event's extended timestamp
- * @event: the event to get the timestamp of
- *
- * Returns the extended timestamp associated with a data event.
- * An extended time_stamp is a 64-bit timestamp represented
- * internally in a special way that makes the best use of space
- * contained within a ring buffer event.  This function decodes
- * it and maps it to a straight u64 value.
- */
-u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event)
-{
-	return rb_event_time_stamp(event);
-}
-
 /* Flag when events were overwritten */
 #define RB_MISSED_EVENTS	(1 << 31)
 /* Missed count stored at end */
@@ -757,6 +742,51 @@ static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set)
 }
 #endif
 
+static inline u64 rb_time_stamp(struct trace_buffer *buffer);
+
+/**
+ * ring_buffer_event_time_stamp - return the event's current time stamp
+ * @buffer: The buffer that the event is on
+ * @event: the event to get the time stamp of
+ *
+ * Note, this must be called after @event is reserved, and before it is
+ * committed to the ring buffer. And must be called from the same
+ * context where the event was reserved (normal, softirq, irq, etc).
+ *
+ * Returns the time stamp associated with the current event.
+ * If the event has an extended time stamp, then that is used as
+ * the time stamp to return.
+ * In the highly unlikely case that the event was nested more than
+ * the max nesting, then the write_stamp of the buffer is returned,
+ * otherwise  current time is returned, but that really neither of
+ * the last two cases should ever happen.
+ */
+u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
+				 struct ring_buffer_event *event)
+{
+	struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[smp_processor_id()];
+	unsigned int nest;
+	u64 ts;
+
+	/* If the event includes an absolute time, then just use that */
+	if (event->type_len == RINGBUF_TYPE_TIME_STAMP)
+		return rb_event_time_stamp(event);
+
+	/* Read the current saved nesting level time stamp */
+	nest = local_read(&cpu_buffer->committing) - 1;
+	if (likely(nest < MAX_NEST))
+		return cpu_buffer->event_stamp[nest];
+
+	WARN_ON_ONCE(1);
+
+	/* Can only fail on 32 bit */
+	if (!rb_time_read(&cpu_buffer->write_stamp, &ts))
+		/* Screw it, just read the current time */
+		ts = rb_time_stamp(cpu_buffer->buffer);
+
+	return ts;
+}
+
 /**
  * ring_buffer_nr_pages - get the number of buffer pages in the ring buffer
  * @buffer: The ring_buffer to get the number of pages from
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 6978aa3ee4c5..45986cb4637e 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -644,7 +644,7 @@ static u64 hist_field_timestamp(struct hist_field *hist_field,
 	struct hist_trigger_data *hist_data = hist_field->hist_data;
 	struct trace_array *tr = hist_data->event_file->tr;
 
-	u64 ts = ring_buffer_event_time_stamp(rbe);
+	u64 ts = ring_buffer_event_time_stamp(buffer, rbe);
 
 	if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr))
 		ts = ns2usecs(ts);
-- 
2.30.1

[for-next][PATCH 05/13] tracing: Use a no_filter_buffering_ref to stop using the filter buffer

[Steven Rostedt]

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

Currently, the trace histograms relies on it using absolute time stamps to
trigger the tracing to not use the temp buffer if filters are set. That's
because the histograms need the full timestamp that is saved in the ring
buffer. That is no longer the case, as the ring_buffer_event_time_stamp()
can now return the time stamp for all events without all triggering a full
absolute time stamp.

Now that the absolute time stamp is an unrelated dependency to not using
the filters. There's nothing about having absolute timestamps to keep from
using the filter buffer. Instead, change the interface to explicitly state
to disable filter buffering that the histogram logic can use.

Link: https://lkml.kernel.org/r/20210316164113.847886563@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c             | 28 ++++++++++++----------------
 kernel/trace/trace.h             |  4 ++--
 kernel/trace/trace_events_hist.c |  6 +++---
 3 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f979220238a5..b15436ff85e8 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2737,12 +2737,13 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb,
 			  unsigned int trace_ctx)
 {
 	struct ring_buffer_event *entry;
+	struct trace_array *tr = trace_file->tr;
 	int val;
 
-	*current_rb = trace_file->tr->array_buffer.buffer;
+	*current_rb = tr->array_buffer.buffer;
 
-	if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
-	     (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
+	if (!tr->no_filter_buffering_ref &&
+	    (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
 	    (entry = this_cpu_read(trace_buffered_event))) {
 		/* Try to use the per cpu buffer first */
 		val = this_cpu_inc_return(trace_buffered_event_cnt);
@@ -6971,31 +6972,26 @@ static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
 	return ret;
 }
 
-int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
+/*
+ * Set or disable using the per CPU trace_buffer_event when possible.
+ */
+int tracing_set_filter_buffering(struct trace_array *tr, bool set)
 {
 	int ret = 0;
 
 	mutex_lock(&trace_types_lock);
 
-	if (abs && tr->time_stamp_abs_ref++)
+	if (set && tr->no_filter_buffering_ref++)
 		goto out;
 
-	if (!abs) {
-		if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
+	if (!set) {
+		if (WARN_ON_ONCE(!tr->no_filter_buffering_ref)) {
 			ret = -EINVAL;
 			goto out;
 		}
 
-		if (--tr->time_stamp_abs_ref)
-			goto out;
+		--tr->no_filter_buffering_ref;
 	}
-
-	ring_buffer_set_time_stamp_abs(tr->array_buffer.buffer, abs);
-
-#ifdef CONFIG_TRACER_MAX_TRACE
-	if (tr->max_buffer.buffer)
-		ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
-#endif
  out:
 	mutex_unlock(&trace_types_lock);
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 798773178d7e..f2a7a72825c7 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -352,7 +352,7 @@ struct trace_array {
 	/* function tracing enabled */
 	int			function_enabled;
 #endif
-	int			time_stamp_abs_ref;
+	int			no_filter_buffering_ref;
 	struct list_head	hist_vars;
 #ifdef CONFIG_TRACER_SNAPSHOT
 	struct cond_snapshot	*cond_snapshot;
@@ -372,7 +372,7 @@ extern int tracing_check_open_get_tr(struct trace_array *tr);
 extern struct trace_array *trace_array_find(const char *instance);
 extern struct trace_array *trace_array_find_get(const char *instance);
 
-extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs);
+extern int tracing_set_filter_buffering(struct trace_array *tr, bool set);
 extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);
 
 extern bool trace_clock_in_ns(struct trace_array *tr);
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 45986cb4637e..c1abd63f1d6c 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -5484,7 +5484,7 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
 			goto out;
 		}
 
-		tracing_set_time_stamp_abs(file->tr, true);
+		tracing_set_filter_buffering(file->tr, true);
 	}
 
 	if (named_data)
@@ -5592,7 +5592,7 @@ static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
 
 	if (hist_data->enable_timestamps) {
 		if (!hist_data->remove || unregistered)
-			tracing_set_time_stamp_abs(file->tr, false);
+			tracing_set_filter_buffering(file->tr, false);
 	}
 }
 
@@ -5639,7 +5639,7 @@ static void hist_unreg_all(struct trace_event_file *file)
 
 			update_cond_flag(file);
 			if (hist_data->enable_timestamps)
-				tracing_set_time_stamp_abs(file->tr, false);
+				tracing_set_filter_buffering(file->tr, false);
 			if (test->ops->free)
 				test->ops->free(test->ops, test);
 		}
-- 
2.30.1

[for-next][PATCH 06/13] ring-buffer: Add verifier for using ring_buffer_event_time_stamp()

[Steven Rostedt]

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

The ring_buffer_event_time_stamp() must be only called by an event that has
not been committed yet, and is on the buffer that is passed in. This was
used to help debug converting the histogram logic over to using the new
time stamp code, and was proven to be very useful.

Add a verifier that can check that this is the case, and extra WARN_ONs to
catch unexpected use cases.

Link: https://lkml.kernel.org/r/20210316164113.987294354@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/ring_buffer.c | 56 +++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 8fa2a84f714f..1c61a8cd7b99 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -742,6 +742,48 @@ static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set)
 }
 #endif
 
+/*
+ * Enable this to make sure that the event passed to
+ * ring_buffer_event_time_stamp() is not committed and also
+ * is on the buffer that it passed in.
+ */
+//#define RB_VERIFY_EVENT
+#ifdef RB_VERIFY_EVENT
+static struct list_head *rb_list_head(struct list_head *list);
+static void verify_event(struct ring_buffer_per_cpu *cpu_buffer,
+			 void *event)
+{
+	struct buffer_page *page = cpu_buffer->commit_page;
+	struct buffer_page *tail_page = READ_ONCE(cpu_buffer->tail_page);
+	struct list_head *next;
+	long commit, write;
+	unsigned long addr = (unsigned long)event;
+	bool done = false;
+	int stop = 0;
+
+	/* Make sure the event exists and is not committed yet */
+	do {
+		if (page == tail_page || WARN_ON_ONCE(stop++ > 100))
+			done = true;
+		commit = local_read(&page->page->commit);
+		write = local_read(&page->write);
+		if (addr >= (unsigned long)&page->page->data[commit] &&
+		    addr < (unsigned long)&page->page->data[write])
+			return;
+
+		next = rb_list_head(page->list.next);
+		page = list_entry(next, struct buffer_page, list);
+	} while (!done);
+	WARN_ON_ONCE(1);
+}
+#else
+static inline void verify_event(struct ring_buffer_per_cpu *cpu_buffer,
+			 void *event)
+{
+}
+#endif
+
+
 static inline u64 rb_time_stamp(struct trace_buffer *buffer);
 
 /**
@@ -772,13 +814,19 @@ u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
 	if (event->type_len == RINGBUF_TYPE_TIME_STAMP)
 		return rb_event_time_stamp(event);
 
+	nest = local_read(&cpu_buffer->committing);
+	verify_event(cpu_buffer, event);
+	if (WARN_ON_ONCE(!nest))
+		goto fail;
+
 	/* Read the current saved nesting level time stamp */
-	nest = local_read(&cpu_buffer->committing) - 1;
-	if (likely(nest < MAX_NEST))
+	if (likely(--nest < MAX_NEST))
 		return cpu_buffer->event_stamp[nest];
 
-	WARN_ON_ONCE(1);
+	/* Shouldn't happen, warn if it does */
+	WARN_ONCE(1, "nest (%d) greater than max", nest);
 
+ fail:
 	/* Can only fail on 32 bit */
 	if (!rb_time_read(&cpu_buffer->write_stamp, &ts))
 		/* Screw it, just read the current time */
@@ -2750,7 +2798,7 @@ rb_update_event(struct ring_buffer_per_cpu *cpu_buffer,
 	u64 delta = info->delta;
 	unsigned int nest = local_read(&cpu_buffer->committing) - 1;
 
-	if (nest < MAX_NEST)
+	if (!WARN_ON_ONCE(nest >= MAX_NEST))
 		cpu_buffer->event_stamp[nest] = info->ts;
 
 	/*
-- 
2.30.1

[for-next][PATCH 07/13] tracing: Add tracing_event_time_stamp() API

[Steven Rostedt]

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

Add a tracing_event_time_stamp() API that checks if the event passed in is
not on the ring buffer but a pointer to the per CPU trace_buffered_event
which does not have its time stamp set yet.

If it is a pointer to the trace_buffered_event, then just return the
current time stamp that the ring buffer would produce.

Otherwise, return the time stamp from the event.

Link: https://lkml.kernel.org/r/20210316164114.131996180@goodmis.org

Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c | 8 ++++++++
 kernel/trace/trace.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b15436ff85e8..90ae3140756e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -6972,6 +6972,14 @@ static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
 	return ret;
 }
 
+u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe)
+{
+	if (rbe == this_cpu_read(trace_buffered_event))
+		return ring_buffer_time_stamp(buffer, smp_processor_id());
+
+	return ring_buffer_event_time_stamp(buffer, rbe);
+}
+
 /*
  * Set or disable using the per CPU trace_buffer_event when possible.
  */
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f2a7a72825c7..0d8f54f49a3a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -372,6 +372,7 @@ extern int tracing_check_open_get_tr(struct trace_array *tr);
 extern struct trace_array *trace_array_find(const char *instance);
 extern struct trace_array *trace_array_find_get(const char *instance);
 
+extern u64 tracing_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *rbe);
 extern int tracing_set_filter_buffering(struct trace_array *tr, bool set);
 extern int tracing_set_clock(struct trace_array *tr, const char *clockstr);
 
-- 
2.30.1

[for-next][PATCH 08/13] bootconfig: Update prototype of setup_boot_config()

[Steven Rostedt]

From: Cao jin <jojing64@gmail.com>

Parameter "cmdline" has no use, drop it.

Link: https://lkml.kernel.org/r/20210311085213.27680-1-jojing64@gmail.com

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Cao jin <jojing64@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 init/main.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/init/main.c b/init/main.c
index 53b278845b88..407976d8669e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -405,7 +405,7 @@ static int __init bootconfig_params(char *param, char *val,
 	return 0;
 }
 
-static void __init setup_boot_config(const char *cmdline)
+static void __init setup_boot_config(void)
 {
 	static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
 	const char *msg;
@@ -472,7 +472,7 @@ static void __init setup_boot_config(const char *cmdline)
 
 #else
 
-static void __init setup_boot_config(const char *cmdline)
+static void __init setup_boot_config(void)
 {
 	/* Remove bootconfig data from initrd */
 	get_boot_config_from_initrd(NULL, NULL);
@@ -872,7 +872,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void)
 	pr_notice("%s", linux_banner);
 	early_security_init();
 	setup_arch(&command_line);
-	setup_boot_config(command_line);
+	setup_boot_config();
 	setup_command_line(command_line);
 	setup_nr_cpu_ids();
 	setup_per_cpu_areas();
-- 
2.30.1

[for-next][PATCH 09/13] tools/latency-collector: Remove unneeded semicolon

[Steven Rostedt]

From: Xu Wang <vulab@iscas.ac.cn>

Fix semicolon.cocci warning:
tools/tracing/latency/latency-collector.c:1021:2-3: Unneeded semicolon

Link: https://lkml.kernel.org/r/20210308022459.59881-1-vulab@iscas.ac.cn

Reviewed-by: Viktor Rosendahl <Viktor.Rosendahl@bmw.de>
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 tools/tracing/latency/latency-collector.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/tracing/latency/latency-collector.c b/tools/tracing/latency/latency-collector.c
index b69de9263ee6..3a2e6bb781a8 100644
--- a/tools/tracing/latency/latency-collector.c
+++ b/tools/tracing/latency/latency-collector.c
@@ -1018,7 +1018,7 @@ static long go_to_sleep(const struct entry *req)
 		cond_timedwait(&printstate.cond, &printstate.mutex, &future);
 		if (time_has_passed(&future))
 			break;
-	};
+	}
 
 	if (printstate_has_new_req_arrived(req))
 		delay = -1;
@@ -1941,7 +1941,7 @@ static void scan_arguments(int argc, char *argv[])
 			if (value < 0) {
 				warnx("TIME must be >= 0\n");
 				show_usage();
-				;
+				exit(0);
 			}
 			trace_enable = true;
 			use_random_sleep = true;
-- 
2.30.1

[for-next][PATCH 10/13] ftrace: Fix spelling mistake "disabed" -> "disabled"

[Steven Rostedt]

From: Colin Ian King <colin.king@canonical.com>

There is a spelling mistake in a comment, fix it.

Link: https://lkml.kernel.org/r/20210311094022.5978-1-colin.king@canonical.com

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 arch/csky/kernel/probes/ftrace.c  | 2 +-
 arch/riscv/kernel/probes/ftrace.c | 2 +-
 arch/x86/kernel/kprobes/ftrace.c  | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/csky/kernel/probes/ftrace.c b/arch/csky/kernel/probes/ftrace.c
index ae2b1c7b3b5c..ef2bb9bd9605 100644
--- a/arch/csky/kernel/probes/ftrace.c
+++ b/arch/csky/kernel/probes/ftrace.c
@@ -9,7 +9,7 @@ int arch_check_ftrace_location(struct kprobe *p)
 	return 0;
 }
 
-/* Ftrace callback handler for kprobes -- called under preepmt disabed */
+/* Ftrace callback handler for kprobes -- called under preepmt disabled */
 void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 			   struct ftrace_ops *ops, struct ftrace_regs *fregs)
 {
diff --git a/arch/riscv/kernel/probes/ftrace.c b/arch/riscv/kernel/probes/ftrace.c
index e6372490aa0b..c666e5ecb8da 100644
--- a/arch/riscv/kernel/probes/ftrace.c
+++ b/arch/riscv/kernel/probes/ftrace.c
@@ -2,7 +2,7 @@
 
 #include <linux/kprobes.h>
 
-/* Ftrace callback handler for kprobes -- called under preepmt disabed */
+/* Ftrace callback handler for kprobes -- called under preepmt disabled */
 void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 			   struct ftrace_ops *ops, struct ftrace_regs *regs)
 {
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index 373e5fa3ce1f..51c7f5271aee 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -12,7 +12,7 @@
 
 #include "common.h"
 
-/* Ftrace callback handler for kprobes -- called under preepmt disabed */
+/* Ftrace callback handler for kprobes -- called under preepmt disabled */
 void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 			   struct ftrace_ops *ops, struct ftrace_regs *fregs)
 {
-- 
2.30.1

[for-next][PATCH 11/13] tracing: Add check of trace event print fmts for dereferencing pointers

[Steven Rostedt]

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

Trace events record data into the ring buffer at the time of the event. The
trace event has a printf logic to display the recorded data at a much later
time when the user reads the trace file. This makes using dereferencing
pointers unsafe if the dereferenced pointer points to the original source.
The safe way to handle this is to create an array within the trace event and
copy the source into the array. Then the dereference pointer may point to
that array.

As this is a easy mistake to make, a check is added to examine all trace
event print fmts to make sure that they are safe to use. This only checks
the various %p* dereferenced pointers like %pB, %pR, etc. It does not handle
dereferencing of strings, as there are some use cases that are OK to
dereference the source. That will be dealt with differently.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c | 210 ++++++++++++++++++++++++++++++++++++
 1 file changed, 210 insertions(+)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a3563afd412d..f58106eaf8cb 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -217,6 +217,214 @@ int trace_event_get_offsets(struct trace_event_call *call)
 	return tail->offset + tail->size;
 }
 
+/*
+ * Check if the referenced field is an array and return true,
+ * as arrays are OK to dereference.
+ */
+static bool test_field(const char *fmt, struct trace_event_call *call)
+{
+	struct trace_event_fields *field = call->class->fields_array;
+	const char *array_descriptor;
+	const char *p = fmt;
+	int len;
+
+	if (!(len = str_has_prefix(fmt, "REC->")))
+		return false;
+	fmt += len;
+	for (p = fmt; *p; p++) {
+		if (!isalnum(*p) && *p != '_')
+			break;
+	}
+	len = p - fmt;
+
+	for (; field->type; field++) {
+		if (strncmp(field->name, fmt, len) ||
+		    field->name[len])
+			continue;
+		array_descriptor = strchr(field->type, '[');
+		/* This is an array and is OK to dereference. */
+		return array_descriptor != NULL;
+	}
+	return false;
+}
+
+/*
+ * Examine the print fmt of the event looking for unsafe dereference
+ * pointers using %p* that could be recorded in the trace event and
+ * much later referenced after the pointer was freed. Dereferencing
+ * pointers are OK, if it is dereferenced into the event itself.
+ */
+static void test_event_printk(struct trace_event_call *call)
+{
+	u64 dereference_flags = 0;
+	bool first = true;
+	const char *fmt, *c, *r, *a;
+	int parens = 0;
+	char in_quote = 0;
+	int start_arg = 0;
+	int arg = 0;
+	int i;
+
+	fmt = call->print_fmt;
+
+	if (!fmt)
+		return;
+
+	for (i = 0; fmt[i]; i++) {
+		switch (fmt[i]) {
+		case '\\':
+			i++;
+			if (!fmt[i])
+				return;
+			continue;
+		case '"':
+		case '\'':
+			/*
+			 * The print fmt starts with a string that
+			 * is processed first to find %p* usage,
+			 * then after the first string, the print fmt
+			 * contains arguments that are used to check
+			 * if the dereferenced %p* usage is safe.
+			 */
+			if (first) {
+				if (fmt[i] == '\'')
+					continue;
+				if (in_quote) {
+					arg = 0;
+					first = false;
+					/*
+					 * If there was no %p* uses
+					 * the fmt is OK.
+					 */
+					if (!dereference_flags)
+						return;
+				}
+			}
+			if (in_quote) {
+				if (in_quote == fmt[i])
+					in_quote = 0;
+			} else {
+				in_quote = fmt[i];
+			}
+			continue;
+		case '%':
+			if (!first || !in_quote)
+				continue;
+			i++;
+			if (!fmt[i])
+				return;
+			switch (fmt[i]) {
+			case '%':
+				continue;
+			case 'p':
+				/* Find dereferencing fields */
+				switch (fmt[i + 1]) {
+				case 'B': case 'R': case 'r':
+				case 'b': case 'M': case 'm':
+				case 'I': case 'i': case 'E':
+				case 'U': case 'V': case 'N':
+				case 'a': case 'd': case 'D':
+				case 'g': case 't': case 'C':
+				case 'O': case 'f':
+					if (WARN_ONCE(arg == 63,
+						      "Too many args for event: %s",
+						      trace_event_name(call)))
+						return;
+					dereference_flags |= 1ULL << arg;
+				}
+				break;
+			default:
+			{
+				bool star = false;
+				int j;
+
+				/* Increment arg if %*s exists. */
+				for (j = 0; fmt[i + j]; j++) {
+					if (isdigit(fmt[i + j]) ||
+					    fmt[i + j] == '.')
+						continue;
+					if (fmt[i + j] == '*') {
+						star = true;
+						continue;
+					}
+					if ((fmt[i + j] == 's') && star)
+						arg++;
+					break;
+				}
+				break;
+			} /* default */
+
+			} /* switch */
+			arg++;
+			continue;
+		case '(':
+			if (in_quote)
+				continue;
+			parens++;
+			continue;
+		case ')':
+			if (in_quote)
+				continue;
+			parens--;
+			if (WARN_ONCE(parens < 0,
+				      "Paren mismatch for event: %s\narg='%s'\n%*s",
+				      trace_event_name(call),
+				      fmt + start_arg,
+				      (i - start_arg) + 5, "^"))
+				return;
+			continue;
+		case ',':
+			if (in_quote || parens)
+				continue;
+			i++;
+			while (isspace(fmt[i]))
+				i++;
+			start_arg = i;
+			if (!(dereference_flags & (1ULL << arg)))
+				goto next_arg;
+
+			/* Find the REC-> in the argument */
+			c = strchr(fmt + i, ',');
+			r = strstr(fmt + i, "REC->");
+			if (r && (!c || r < c)) {
+				/*
+				 * Addresses of events on the buffer,
+				 * or an array on the buffer is
+				 * OK to dereference.
+				 * There's ways to fool this, but
+				 * this is to catch common mistakes,
+				 * not malicious code.
+				 */
+				a = strchr(fmt + i, '&');
+				if ((a && (a < r)) || test_field(r, call))
+					dereference_flags &= ~(1ULL << arg);
+			}
+		next_arg:
+			i--;
+			arg++;
+		}
+	}
+
+	/*
+	 * If you triggered the below warning, the trace event reported
+	 * uses an unsafe dereference pointer %p*. As the data stored
+	 * at the trace event time may no longer exist when the trace
+	 * event is printed, dereferencing to the original source is
+	 * unsafe. The source of the dereference must be copied into the
+	 * event itself, and the dereference must access the copy instead.
+	 */
+	if (WARN_ON_ONCE(dereference_flags)) {
+		arg = 1;
+		while (!(dereference_flags & 1)) {
+			dereference_flags >>= 1;
+			arg++;
+		}
+		pr_warn("event %s has unsafe dereference of argument %d\n",
+			trace_event_name(call), arg);
+		pr_warn("print_fmt: %s\n", fmt);
+	}
+}
+
 int trace_event_raw_init(struct trace_event_call *call)
 {
 	int id;
@@ -225,6 +433,8 @@ int trace_event_raw_init(struct trace_event_call *call)
 	if (!id)
 		return -ENODEV;
 
+	test_event_printk(call);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(trace_event_raw_init);
-- 
2.30.1

[for-next][PATCH 12/13] seq_buf: Add seq_buf_terminate() API

[Steven Rostedt]

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

In the case that the seq_buf buffer needs to be printed directly, add a way
to make sure that the buffer is safe to read by forcing a nul terminating
character at the end of the string, or the last byte of the buffer if the
string has overflowed.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/linux/seq_buf.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/linux/seq_buf.h b/include/linux/seq_buf.h
index 9d6c28cc4d8f..5b31c5147969 100644
--- a/include/linux/seq_buf.h
+++ b/include/linux/seq_buf.h
@@ -71,6 +71,31 @@ static inline unsigned int seq_buf_used(struct seq_buf *s)
 	return min(s->len, s->size);
 }
 
+/**
+ * seq_buf_terminate - Make sure buffer is nul terminated
+ * @s: the seq_buf descriptor to terminate.
+ *
+ * This makes sure that the buffer in @s is nul terminated and
+ * safe to read as a string.
+ *
+ * Note, if this is called when the buffer has overflowed, then
+ * the last byte of the buffer is zeroed, and the len will still
+ * point passed it.
+ *
+ * After this function is called, s->buffer is safe to use
+ * in string operations.
+ */
+static inline void seq_buf_terminate(struct seq_buf *s)
+{
+	if (WARN_ON(s->size == 0))
+		return;
+
+	if (seq_buf_buffer_left(s))
+		s->buffer[s->len] = 0;
+	else
+		s->buffer[s->size - 1] = 0;
+}
+
 /**
  * seq_buf_get_buf - get buffer to write arbitrary data to
  * @s: the seq_buf handle
-- 
2.30.1

[for-next][PATCH 13/13] tracing: Add a verifier to check string pointers for trace events

[Steven Rostedt]

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

It is a common mistake for someone writing a trace event to save a pointer
to a string in the TP_fast_assign() and then display that string pointer
in the TP_printk() with %s. The problem is that those two events may happen
a long time apart, where the source of the string may no longer exist.

The proper way to handle displaying any string that is not guaranteed to be
in the kernel core rodata section, is to copy it into the ring buffer via
the __string(), __assign_str() and __get_str() helper macros.

Add a check at run time while displaying the TP_printk() of events to make
sure that every %s referenced is safe to dereference, and if it is not,
trigger a warning and only show the address of the pointer, and the
dereferenced string if it can be safely retrieved with a
strncpy_from_kernel_nofault() call.

In order to not have to copy the parsing of vsnprintf() formats, or even
exporting its code, the verifier relies on vsnprintf() being able to
modify the va_list that is passed to it, and it remains modified after it
is called. This is the case for some architectures like x86_64, but other
architectures like x86_32 pass the va_list to vsnprintf() as a value not a
reference, and the verifier can not use it to parse the non string
arguments. Thus, at boot up, it is checked if vsnprintf() modifies the
passed in va_list or not, and a static branch will disable the verifier if
it's not compatible.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/trace/trace.c        | 200 ++++++++++++++++++++++++++++++++++++
 kernel/trace/trace.h        |   3 +
 kernel/trace/trace_output.c |   2 +-
 kernel/trace/trace_printk.c |  11 ++
 4 files changed, 215 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 90ae3140756e..e32f5a49f1cf 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3558,6 +3558,204 @@ static char *trace_iter_expand_format(struct trace_iterator *iter)
 	return tmp;
 }
 
+/* Returns true if the string is safe to dereference from an event */
+static bool trace_safe_str(struct trace_iterator *iter, const char *str)
+{
+	unsigned long addr = (unsigned long)str;
+	struct trace_event *trace_event;
+	struct trace_event_call *event;
+
+	/* OK if part of the event data */
+	if ((addr >= (unsigned long)iter->ent) &&
+	    (addr < (unsigned long)iter->ent + iter->ent_size))
+		return true;
+
+	/* OK if part of the temp seq buffer */
+	if ((addr >= (unsigned long)iter->tmp_seq.buffer) &&
+	    (addr < (unsigned long)iter->tmp_seq.buffer + PAGE_SIZE))
+		return true;
+
+	/* Core rodata can not be freed */
+	if (is_kernel_rodata(addr))
+		return true;
+
+	if (trace_is_tracepoint_string(str))
+		return true;
+
+	/*
+	 * Now this could be a module event, referencing core module
+	 * data, which is OK.
+	 */
+	if (!iter->ent)
+		return false;
+
+	trace_event = ftrace_find_event(iter->ent->type);
+	if (!trace_event)
+		return false;
+
+	event = container_of(trace_event, struct trace_event_call, event);
+	if (!event->mod)
+		return false;
+
+	/* Would rather have rodata, but this will suffice */
+	if (within_module_core(addr, event->mod))
+		return true;
+
+	return false;
+}
+
+static const char *show_buffer(struct trace_seq *s)
+{
+	struct seq_buf *seq = &s->seq;
+
+	seq_buf_terminate(seq);
+
+	return seq->buffer;
+}
+
+static DEFINE_STATIC_KEY_FALSE(trace_no_verify);
+
+static int test_can_verify_check(const char *fmt, ...)
+{
+	char buf[16];
+	va_list ap;
+	int ret;
+
+	/*
+	 * The verifier is dependent on vsnprintf() modifies the va_list
+	 * passed to it, where it is sent as a reference. Some architectures
+	 * (like x86_32) passes it by value, which means that vsnprintf()
+	 * does not modify the va_list passed to it, and the verifier
+	 * would then need to be able to understand all the values that
+	 * vsnprintf can use. If it is passed by value, then the verifier
+	 * is disabled.
+	 */
+	va_start(ap, fmt);
+	vsnprintf(buf, 16, "%d", ap);
+	ret = va_arg(ap, int);
+	va_end(ap);
+
+	return ret;
+}
+
+static void test_can_verify(void)
+{
+	if (!test_can_verify_check("%d %d", 0, 1)) {
+		pr_info("trace event string verifier disabled\n");
+		static_branch_inc(&trace_no_verify);
+	}
+}
+
+/**
+ * trace_check_vprintf - Check dereferenced strings while writing to the seq buffer
+ * @iter: The iterator that holds the seq buffer and the event being printed
+ * @fmt: The format used to print the event
+ * @ap: The va_list holding the data to print from @fmt.
+ *
+ * This writes the data into the @iter->seq buffer using the data from
+ * @fmt and @ap. If the format has a %s, then the source of the string
+ * is examined to make sure it is safe to print, otherwise it will
+ * warn and print "[UNSAFE MEMORY]" in place of the dereferenced string
+ * pointer.
+ */
+void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
+			 va_list ap)
+{
+	const char *p = fmt;
+	const char *str;
+	int i, j;
+
+	if (WARN_ON_ONCE(!fmt))
+		return;
+
+	if (static_branch_unlikely(&trace_no_verify))
+		goto print;
+
+	/* Don't bother checking when doing a ftrace_dump() */
+	if (iter->fmt == static_fmt_buf)
+		goto print;
+
+	while (*p) {
+		j = 0;
+
+		/* We only care about %s and variants */
+		for (i = 0; p[i]; i++) {
+			if (i + 1 >= iter->fmt_size) {
+				/*
+				 * If we can't expand the copy buffer,
+				 * just print it.
+				 */
+				if (!trace_iter_expand_format(iter))
+					goto print;
+			}
+
+			if (p[i] == '\\' && p[i+1]) {
+				i++;
+				continue;
+			}
+			if (p[i] == '%') {
+				/* Need to test cases like %08.*s */
+				for (j = 1; p[i+j]; j++) {
+					if (isdigit(p[i+j]) ||
+					    p[i+j] == '*' ||
+					    p[i+j] == '.')
+						continue;
+					break;
+				}
+				if (p[i+j] == 's')
+					break;
+			}
+			j = 0;
+		}
+		/* If no %s found then just print normally */
+		if (!p[i])
+			break;
+
+		/* Copy up to the %s, and print that */
+		strncpy(iter->fmt, p, i);
+		iter->fmt[i] = '\0';
+		trace_seq_vprintf(&iter->seq, iter->fmt, ap);
+
+		/* The ap now points to the string data of the %s */
+		str = va_arg(ap, const char *);
+
+		/*
+		 * If you hit this warning, it is likely that the
+		 * trace event in question used %s on a string that
+		 * was saved at the time of the event, but may not be
+		 * around when the trace is read. Use __string(),
+		 * __assign_str() and __get_str() helpers in the TRACE_EVENT()
+		 * instead. See samples/trace_events/trace-events-sample.h
+		 * for reference.
+		 */
+		if (WARN_ONCE(!trace_safe_str(iter, str),
+			      "fmt: '%s' current_buffer: '%s'",
+			      fmt, show_buffer(&iter->seq))) {
+			int ret;
+
+			/* Try to safely read the string */
+			ret = strncpy_from_kernel_nofault(iter->fmt, str,
+							  iter->fmt_size);
+			if (ret < 0)
+				trace_seq_printf(&iter->seq, "(0x%px)", str);
+			else
+				trace_seq_printf(&iter->seq, "(0x%px:%s)",
+						 str, iter->fmt);
+			str = "[UNSAFE-MEMORY]";
+			strcpy(iter->fmt, "%s");
+		} else {
+			strncpy(iter->fmt, p + i, j + 1);
+			iter->fmt[j+1] = '\0';
+		}
+		trace_seq_printf(&iter->seq, iter->fmt, str);
+
+		p += i + j + 1;
+	}
+ print:
+	if (*p)
+		trace_seq_vprintf(&iter->seq, p, ap);
+}
+
 const char *trace_event_format(struct trace_iterator *iter, const char *fmt)
 {
 	const char *p, *new_fmt;
@@ -9675,6 +9873,8 @@ __init static int tracer_alloc_buffers(void)
 
 	register_snapshot_cmd();
 
+	test_can_verify();
+
 	return 0;
 
 out_free_savedcmd:
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 0d8f54f49a3a..2952bd92bc62 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -582,7 +582,10 @@ struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 void trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer,
 					struct ring_buffer_event *event);
 
+bool trace_is_tracepoint_string(const char *str);
 const char *trace_event_format(struct trace_iterator *iter, const char *fmt);
+void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
+			 va_list ap);
 
 int trace_empty(struct trace_iterator *iter);
 
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 61255bad7e01..a0146e1fffdf 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -317,7 +317,7 @@ void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...)
 	va_list ap;
 
 	va_start(ap, fmt);
-	trace_seq_vprintf(&iter->seq, trace_event_format(iter, fmt), ap);
+	trace_check_vprintf(iter, trace_event_format(iter, fmt), ap);
 	va_end(ap);
 }
 EXPORT_SYMBOL(trace_event_printf);
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index ff32476df072..4b320fe7df70 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -251,6 +251,17 @@ int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
 }
 EXPORT_SYMBOL_GPL(__ftrace_vprintk);
 
+bool trace_is_tracepoint_string(const char *str)
+{
+	const char **ptr = __start___tracepoint_str;
+
+	for (ptr = __start___tracepoint_str; ptr < __stop___tracepoint_str; ptr++) {
+		if (str == *ptr)
+			return true;
+	}
+	return false;
+}
+
 static const char **find_next(void *v, loff_t *pos)
 {
 	const char **fmt = v;
-- 
2.30.1