Merge tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "New tracing features:

   - The ring buffer is no longer disabled when reading the trace file.

     The trace_pipe file was made to be used for live tracing and
     reading as it acted like the normal producer/consumer. As the trace
     file would not consume the data, the easy way of handling it was to
     just disable writes to the ring buffer.

     This came to a surprise to the BPF folks who complained about lost
     events due to reading. This is no longer an issue. If someone wants
     to keep the old disabling there's a new option "pause-on-trace"
     that can be set.

   - New set_ftrace_notrace_pid file. PIDs in this file will not be
     traced by the function tracer.

     Similar to set_ftrace_pid, which makes the function tracer only
     trace those tasks with PIDs in the file, the set_ftrace_notrace_pid
     does the reverse.

   - New set_event_notrace_pid file. PIDs in this file will cause events
     not to be traced if triggered by a task with a matching PID.

     Similar to the set_event_pid file but will not be traced. Note,
     sched_waking and sched_switch events may still be traced if one of
     the tasks referenced by those events contains a PID that is allowed
     to be traced.

  Tracing related features:

   - New bootconfig option, that is attached to the initrd file.

     If bootconfig is on the command line, then the initrd file is
     searched looking for a bootconfig appended at the end.

   - New GPU tracepoint infrastructure to help the gfx drivers to get
     off debugfs (acked by Greg Kroah-Hartman)

  And other minor updates and fixes"

* tag 'trace-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
  tracing: Do not allocate buffer in trace_find_next_entry() in atomic
  tracing: Add documentation on set_ftrace_notrace_pid and set_event_notrace_pid
  selftests/ftrace: Add test to test new set_event_notrace_pid file
  selftests/ftrace: Add test to test new set_ftrace_notrace_pid file
  tracing: Create set_event_notrace_pid to not trace tasks
  ftrace: Create set_ftrace_notrace_pid to not trace tasks
  ftrace: Make function trace pid filtering a bit more exact
  ftrace/kprobe: Show the maxactive number on kprobe_events
  tracing: Have the document reflect that the trace file keeps tracing enabled
  ring-buffer/tracing: Have iterator acknowledge dropped events
  tracing: Do not disable tracing when reading the trace file
  ring-buffer: Do not disable recording when there is an iterator
  ring-buffer: Make resize disable per cpu buffer instead of total buffer
  ring-buffer: Optimize rb_iter_head_event()
  ring-buffer: Do not die if rb_iter_peek() fails more than thrice
  ring-buffer: Have rb_iter_head_event() handle concurrent writer
  ring-buffer: Add page_stamp to iterator for synchronization
  ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()
  ring-buffer: Have ring_buffer_empty() not depend on tracing stopped
  tracing: Save off entry when peeking at next entry
  ...

10 files changed, 714 insertions, 205 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fd81c7de77a7..041694a1eb74 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -102,7 +102,7 @@ static bool ftrace_pids_enabled(struct ftrace_ops *ops)
 
 	tr = ops->private;
 
-	return tr->function_pids != NULL;
+	return tr->function_pids != NULL || tr->function_no_pids != NULL;
 }
 
 static void ftrace_update_trampoline(struct ftrace_ops *ops);
@@ -139,13 +139,23 @@ static inline void ftrace_ops_init(struct ftrace_ops *ops)
 #endif
 }
 
+#define FTRACE_PID_IGNORE	-1
+#define FTRACE_PID_TRACE	-2
+
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 			    struct ftrace_ops *op, struct pt_regs *regs)
 {
 	struct trace_array *tr = op->private;
+	int pid;
 
-	if (tr && this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid))
-		return;
+	if (tr) {
+		pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
+		if (pid == FTRACE_PID_IGNORE)
+			return;
+		if (pid != FTRACE_PID_TRACE &&
+		    pid != current->pid)
+			return;
+	}
 
 	op->saved_func(ip, parent_ip, op, regs);
 }
@@ -6923,11 +6933,17 @@ ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
 {
 	struct trace_array *tr = data;
 	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
 
 	pid_list = rcu_dereference_sched(tr->function_pids);
+	no_pid_list = rcu_dereference_sched(tr->function_no_pids);
 
-	this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
-		       trace_ignore_this_task(pid_list, next));
+	if (trace_ignore_this_task(pid_list, no_pid_list, next))
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       FTRACE_PID_IGNORE);
+	else
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       next->pid);
 }
 
 static void
@@ -6940,6 +6956,9 @@ ftrace_pid_follow_sched_process_fork(void *data,
 
 	pid_list = rcu_dereference_sched(tr->function_pids);
 	trace_filter_add_remove_task(pid_list, self, task);
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
 }
 
 static void
@@ -6950,6 +6969,9 @@ ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
 
 	pid_list = rcu_dereference_sched(tr->function_pids);
 	trace_filter_add_remove_task(pid_list, NULL, task);
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
 }
 
 void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
@@ -6967,42 +6989,57 @@ void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
 	}
 }
 
-static void clear_ftrace_pids(struct trace_array *tr)
+static void clear_ftrace_pids(struct trace_array *tr, int type)
 {
 	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
 	int cpu;
 
 	pid_list = rcu_dereference_protected(tr->function_pids,
 					     lockdep_is_held(&ftrace_lock));
-	if (!pid_list)
+	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
+						lockdep_is_held(&ftrace_lock));
+
+	/* Make sure there's something to do */
+	if (!pid_type_enabled(type, pid_list, no_pid_list))
 		return;
 
-	unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
+	/* See if the pids still need to be checked after this */
+	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
+		unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
+	}
 
-	for_each_possible_cpu(cpu)
-		per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = false;
+	if (type & TRACE_PIDS)
+		rcu_assign_pointer(tr->function_pids, NULL);
 
-	rcu_assign_pointer(tr->function_pids, NULL);
+	if (type & TRACE_NO_PIDS)
+		rcu_assign_pointer(tr->function_no_pids, NULL);
 
 	/* Wait till all users are no longer using pid filtering */
 	synchronize_rcu();
 
-	trace_free_pid_list(pid_list);
+	if ((type & TRACE_PIDS) && pid_list)
+		trace_free_pid_list(pid_list);
+
+	if ((type & TRACE_NO_PIDS) && no_pid_list)
+		trace_free_pid_list(no_pid_list);
 }
 
 void ftrace_clear_pids(struct trace_array *tr)
 {
 	mutex_lock(&ftrace_lock);
 
-	clear_ftrace_pids(tr);
+	clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
 
 	mutex_unlock(&ftrace_lock);
 }
 
-static void ftrace_pid_reset(struct trace_array *tr)
+static void ftrace_pid_reset(struct trace_array *tr, int type)
 {
 	mutex_lock(&ftrace_lock);
-	clear_ftrace_pids(tr);
+	clear_ftrace_pids(tr, type);
 
 	ftrace_update_pid_func();
 	ftrace_startup_all(0);
@@ -7066,9 +7103,45 @@ static const struct seq_operations ftrace_pid_sops = {
 	.show = fpid_show,
 };
 
-static int
-ftrace_pid_open(struct inode *inode, struct file *file)
+static void *fnpid_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&ftrace_lock);
+	rcu_read_lock_sched();
+
+	pid_list = rcu_dereference_sched(tr->function_no_pids);
+
+	if (!pid_list)
+		return !(*pos) ? FTRACE_NO_PIDS : NULL;
+
+	return trace_pid_start(pid_list, pos);
+}
+
+static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
 {
+	struct trace_array *tr = m->private;
+	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
+
+	if (v == FTRACE_NO_PIDS) {
+		(*pos)++;
+		return NULL;
+	}
+	return trace_pid_next(pid_list, v, pos);
+}
+
+static const struct seq_operations ftrace_no_pid_sops = {
+	.start = fnpid_start,
+	.next = fnpid_next,
+	.stop = fpid_stop,
+	.show = fpid_show,
+};
+
+static int pid_open(struct inode *inode, struct file *file, int type)
+{
+	const struct seq_operations *seq_ops;
 	struct trace_array *tr = inode->i_private;
 	struct seq_file *m;
 	int ret = 0;
@@ -7079,9 +7152,18 @@ ftrace_pid_open(struct inode *inode, struct file *file)
 
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
-		ftrace_pid_reset(tr);
+		ftrace_pid_reset(tr, type);
+
+	switch (type) {
+	case TRACE_PIDS:
+		seq_ops = &ftrace_pid_sops;
+		break;
+	case TRACE_NO_PIDS:
+		seq_ops = &ftrace_no_pid_sops;
+		break;
+	}
 
-	ret = seq_open(file, &ftrace_pid_sops);
+	ret = seq_open(file, seq_ops);
 	if (ret < 0) {
 		trace_array_put(tr);
 	} else {
@@ -7093,10 +7175,23 @@ ftrace_pid_open(struct inode *inode, struct file *file)
 	return ret;
 }
 
+static int
+ftrace_pid_open(struct inode *inode, struct file *file)
+{
+	return pid_open(inode, file, TRACE_PIDS);
+}
+
+static int
+ftrace_no_pid_open(struct inode *inode, struct file *file)
+{
+	return pid_open(inode, file, TRACE_NO_PIDS);
+}
+
 static void ignore_task_cpu(void *data)
 {
 	struct trace_array *tr = data;
 	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
 
 	/*
 	 * This function is called by on_each_cpu() while the
@@ -7104,18 +7199,25 @@ static void ignore_task_cpu(void *data)
 	 */
 	pid_list = rcu_dereference_protected(tr->function_pids,
 					     mutex_is_locked(&ftrace_lock));
+	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
+						mutex_is_locked(&ftrace_lock));
 
-	this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
-		       trace_ignore_this_task(pid_list, current));
+	if (trace_ignore_this_task(pid_list, no_pid_list, current))
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       FTRACE_PID_IGNORE);
+	else
+		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
+			       current->pid);
 }
 
 static ssize_t
-ftrace_pid_write(struct file *filp, const char __user *ubuf,
-		   size_t cnt, loff_t *ppos)
+pid_write(struct file *filp, const char __user *ubuf,
+	  size_t cnt, loff_t *ppos, int type)
 {
 	struct seq_file *m = filp->private_data;
 	struct trace_array *tr = m->private;
-	struct trace_pid_list *filtered_pids = NULL;
+	struct trace_pid_list *filtered_pids;
+	struct trace_pid_list *other_pids;
 	struct trace_pid_list *pid_list;
 	ssize_t ret;
 
@@ -7124,19 +7226,39 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
 
 	mutex_lock(&ftrace_lock);
 
-	filtered_pids = rcu_dereference_protected(tr->function_pids,
+	switch (type) {
+	case TRACE_PIDS:
+		filtered_pids = rcu_dereference_protected(tr->function_pids,
+					     lockdep_is_held(&ftrace_lock));
+		other_pids = rcu_dereference_protected(tr->function_no_pids,
+					     lockdep_is_held(&ftrace_lock));
+		break;
+	case TRACE_NO_PIDS:
+		filtered_pids = rcu_dereference_protected(tr->function_no_pids,
+					     lockdep_is_held(&ftrace_lock));
+		other_pids = rcu_dereference_protected(tr->function_pids,
 					     lockdep_is_held(&ftrace_lock));
+		break;
+	}
 
 	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
 	if (ret < 0)
 		goto out;
 
-	rcu_assign_pointer(tr->function_pids, pid_list);
+	switch (type) {
+	case TRACE_PIDS:
+		rcu_assign_pointer(tr->function_pids, pid_list);
+		break;
+	case TRACE_NO_PIDS:
+		rcu_assign_pointer(tr->function_no_pids, pid_list);
+		break;
+	}
+
 
 	if (filtered_pids) {
 		synchronize_rcu();
 		trace_free_pid_list(filtered_pids);
-	} else if (pid_list) {
+	} else if (pid_list && !other_pids) {
 		/* Register a probe to set whether to ignore the tracing of a task */
 		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
 	}
@@ -7159,6 +7281,20 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
 	return ret;
 }
 
+static ssize_t
+ftrace_pid_write(struct file *filp, const char __user *ubuf,
+		 size_t cnt, loff_t *ppos)
+{
+	return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
+}
+
+static ssize_t
+ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
+}
+
 static int
 ftrace_pid_release(struct inode *inode, struct file *file)
 {
@@ -7177,10 +7313,20 @@ static const struct file_operations ftrace_pid_fops = {
 	.release	= ftrace_pid_release,
 };
 
+static const struct file_operations ftrace_no_pid_fops = {
+	.open		= ftrace_no_pid_open,
+	.write		= ftrace_no_pid_write,
+	.read		= seq_read,
+	.llseek		= tracing_lseek,
+	.release	= ftrace_pid_release,
+};
+
 void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
 {
 	trace_create_file("set_ftrace_pid", 0644, d_tracer,
 			    tr, &ftrace_pid_fops);
+	trace_create_file("set_ftrace_notrace_pid", 0644, d_tracer,
+			    tr, &ftrace_no_pid_fops);
 }
 
 void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 61f0e92ace99..6f0b42ceeb00 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -441,6 +441,7 @@ enum {
 struct ring_buffer_per_cpu {
 	int				cpu;
 	atomic_t			record_disabled;
+	atomic_t			resize_disabled;
 	struct trace_buffer	*buffer;
 	raw_spinlock_t			reader_lock;	/* serialize readers */
 	arch_spinlock_t			lock;
@@ -484,7 +485,6 @@ struct trace_buffer {
 	unsigned			flags;
 	int				cpus;
 	atomic_t			record_disabled;
-	atomic_t			resize_disabled;
 	cpumask_var_t			cpumask;
 
 	struct lock_class_key		*reader_lock_key;
@@ -503,10 +503,14 @@ struct trace_buffer {
 struct ring_buffer_iter {
 	struct ring_buffer_per_cpu	*cpu_buffer;
 	unsigned long			head;
+	unsigned long			next_event;
 	struct buffer_page		*head_page;
 	struct buffer_page		*cache_reader_page;
 	unsigned long			cache_read;
 	u64				read_stamp;
+	u64				page_stamp;
+	struct ring_buffer_event	*event;
+	int				missed_events;
 };
 
 /**
@@ -1737,18 +1741,24 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 
 	size = nr_pages * BUF_PAGE_SIZE;
 
-	/*
-	 * Don't succeed if resizing is disabled, as a reader might be
-	 * manipulating the ring buffer and is expecting a sane state while
-	 * this is true.
-	 */
-	if (atomic_read(&buffer->resize_disabled))
-		return -EBUSY;
-
 	/* prevent another thread from changing buffer sizes */
 	mutex_lock(&buffer->mutex);
 
+
 	if (cpu_id == RING_BUFFER_ALL_CPUS) {
+		/*
+		 * Don't succeed if resizing is disabled, as a reader might be
+		 * manipulating the ring buffer and is expecting a sane state while
+		 * this is true.
+		 */
+		for_each_buffer_cpu(buffer, cpu) {
+			cpu_buffer = buffer->buffers[cpu];
+			if (atomic_read(&cpu_buffer->resize_disabled)) {
+				err = -EBUSY;
+				goto out_err_unlock;
+			}
+		}
+
 		/* calculate the pages to update */
 		for_each_buffer_cpu(buffer, cpu) {
 			cpu_buffer = buffer->buffers[cpu];
@@ -1816,6 +1826,16 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 		if (nr_pages == cpu_buffer->nr_pages)
 			goto out;
 
+		/*
+		 * Don't succeed if resizing is disabled, as a reader might be
+		 * manipulating the ring buffer and is expecting a sane state while
+		 * this is true.
+		 */
+		if (atomic_read(&cpu_buffer->resize_disabled)) {
+			err = -EBUSY;
+			goto out_err_unlock;
+		}
+
 		cpu_buffer->nr_pages_to_update = nr_pages -
 						cpu_buffer->nr_pages;
 
@@ -1885,6 +1905,7 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size,
 			free_buffer_page(bpage);
 		}
 	}
+ out_err_unlock:
 	mutex_unlock(&buffer->mutex);
 	return err;
 }
@@ -1913,15 +1934,63 @@ rb_reader_event(struct ring_buffer_per_cpu *cpu_buffer)
 			       cpu_buffer->reader_page->read);
 }
 
-static __always_inline struct ring_buffer_event *
-rb_iter_head_event(struct ring_buffer_iter *iter)
+static __always_inline unsigned rb_page_commit(struct buffer_page *bpage)
 {
-	return __rb_page_index(iter->head_page, iter->head);
+	return local_read(&bpage->page->commit);
 }
 
-static __always_inline unsigned rb_page_commit(struct buffer_page *bpage)
+static struct ring_buffer_event *
+rb_iter_head_event(struct ring_buffer_iter *iter)
 {
-	return local_read(&bpage->page->commit);
+	struct ring_buffer_event *event;
+	struct buffer_page *iter_head_page = iter->head_page;
+	unsigned long commit;
+	unsigned length;
+
+	if (iter->head != iter->next_event)
+		return iter->event;
+
+	/*
+	 * When the writer goes across pages, it issues a cmpxchg which
+	 * is a mb(), which will synchronize with the rmb here.
+	 * (see rb_tail_page_update() and __rb_reserve_next())
+	 */
+	commit = rb_page_commit(iter_head_page);
+	smp_rmb();
+	event = __rb_page_index(iter_head_page, iter->head);
+	length = rb_event_length(event);
+
+	/*
+	 * READ_ONCE() doesn't work on functions and we don't want the
+	 * compiler doing any crazy optimizations with length.
+	 */
+	barrier();
+
+	if ((iter->head + length) > commit || length > BUF_MAX_DATA_SIZE)
+		/* Writer corrupted the read? */
+		goto reset;
+
+	memcpy(iter->event, event, length);
+	/*
+	 * If the page stamp is still the same after this rmb() then the
+	 * event was safely copied without the writer entering the page.
+	 */
+	smp_rmb();
+
+	/* Make sure the page didn't change since we read this */
+	if (iter->page_stamp != iter_head_page->page->time_stamp ||
+	    commit > rb_page_commit(iter_head_page))
+		goto reset;
+
+	iter->next_event = iter->head + length;
+	return iter->event;
+ reset:
+	/* Reset to the beginning */
+	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
+	iter->head = 0;
+	iter->next_event = 0;
+	iter->missed_events = 1;
+	return NULL;
 }
 
 /* Size is determined by what has been committed */
@@ -1959,8 +2028,9 @@ static void rb_inc_iter(struct ring_buffer_iter *iter)
 	else
 		rb_inc_page(cpu_buffer, &iter->head_page);
 
-	iter->read_stamp = iter->head_page->page->time_stamp;
+	iter->page_stamp = iter->read_stamp = iter->head_page->page->time_stamp;
 	iter->head = 0;
+	iter->next_event = 0;
 }
 
 /*
@@ -3547,14 +3617,18 @@ static void rb_iter_reset(struct ring_buffer_iter *iter)
 	/* Iterator usage is expected to have record disabled */
 	iter->head_page = cpu_buffer->reader_page;
 	iter->head = cpu_buffer->reader_page->read;
+	iter->next_event = iter->head;
 
 	iter->cache_reader_page = iter->head_page;
 	iter->cache_read = cpu_buffer->read;
 
-	if (iter->head)
+	if (iter->head) {
 		iter->read_stamp = cpu_buffer->read_stamp;
-	else
+		iter->page_stamp = cpu_buffer->reader_page->page->time_stamp;
+	} else {
 		iter->read_stamp = iter->head_page->page->time_stamp;
+		iter->page_stamp = iter->read_stamp;
+	}
 }
 
 /**
@@ -3590,17 +3664,38 @@ int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
 	struct buffer_page *reader;
 	struct buffer_page *head_page;
 	struct buffer_page *commit_page;
+	struct buffer_page *curr_commit_page;
 	unsigned commit;
+	u64 curr_commit_ts;
+	u64 commit_ts;
 
 	cpu_buffer = iter->cpu_buffer;
-
-	/* Remember, trace recording is off when iterator is in use */
 	reader = cpu_buffer->reader_page;
 	head_page = cpu_buffer->head_page;
 	commit_page = cpu_buffer->commit_page;
+	commit_ts = commit_page->page->time_stamp;
+
+	/*
+	 * When the writer goes across pages, it issues a cmpxchg which
+	 * is a mb(), which will synchronize with the rmb here.
+	 * (see rb_tail_page_update())
+	 */
+	smp_rmb();
 	commit = rb_page_commit(commit_page);
+	/* We want to make sure that the commit page doesn't change */
+	smp_rmb();
 
-	return ((iter->head_page == commit_page && iter->head == commit) ||
+	/* Make sure commit page didn't change */
+	curr_commit_page = READ_ONCE(cpu_buffer->commit_page);
+	curr_commit_ts = READ_ONCE(curr_commit_page->page->time_stamp);
+
+	/* If the commit page changed, then there's more data */
+	if (curr_commit_page != commit_page ||
+	    curr_commit_ts != commit_ts)
+		return 0;
+
+	/* Still racy, as it may return a false positive, but that's OK */
+	return ((iter->head_page == commit_page && iter->head >= commit) ||
 		(iter->head_page == reader && commit_page == head_page &&
 		 head_page->read == commit &&
 		 iter->head == rb_page_commit(cpu_buffer->reader_page)));
@@ -3828,15 +3923,22 @@ static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
 static void rb_advance_iter(struct ring_buffer_iter *iter)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
-	struct ring_buffer_event *event;
-	unsigned length;
 
 	cpu_buffer = iter->cpu_buffer;
 
+	/* If head == next_event then we need to jump to the next event */
+	if (iter->head == iter->next_event) {
+		/* If the event gets overwritten again, there's nothing to do */
+		if (rb_iter_head_event(iter) == NULL)
+			return;
+	}
+
+	iter->head = iter->next_event;
+
 	/*
 	 * Check if we are at the end of the buffer.
 	 */
-	if (iter->head >= rb_page_size(iter->head_page)) {
+	if (iter->next_event >= rb_page_size(iter->head_page)) {
 		/* discarded commits can make the page empty */
 		if (iter->head_page == cpu_buffer->commit_page)
 			return;
@@ -3844,27 +3946,7 @@ static void rb_advance_iter(struct ring_buffer_iter *iter)
 		return;
 	}
 
-	event = rb_iter_head_event(iter);
-
-	length = rb_event_length(event);
-
-	/*
-	 * This should not be called to advance the header if we are
-	 * at the tail of the buffer.
-	 */
-	if (RB_WARN_ON(cpu_buffer,
-		       (iter->head_page == cpu_buffer->commit_page) &&
-		       (iter->head + length > rb_commit_index(cpu_buffer))))
-		return;
-
-	rb_update_iter_read_stamp(iter, event);
-
-	iter->head += length;
-
-	/* check for end of page padding */
-	if ((iter->head >= rb_page_size(iter->head_page)) &&
-	    (iter->head_page != cpu_buffer->commit_page))
-		rb_inc_iter(iter);
+	rb_update_iter_read_stamp(iter, iter->event);
 }
 
 static int rb_lost_events(struct ring_buffer_per_cpu *cpu_buffer)
@@ -3952,6 +4034,7 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct ring_buffer_event *event;
 	int nr_loops = 0;
+	bool failed = false;
 
 	if (ts)
 		*ts = 0;
@@ -3978,10 +4061,14 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 	 * to a data event, we should never loop more than three times.
 	 * Once for going to next page, once on time extend, and
 	 * finally once to get the event.
-	 * (We never hit the following condition more than thrice).
+	 * We should never hit the following condition more than thrice,
+	 * unless the buffer is very small, and there's a writer
+	 * that is causing the reader to fail getting an event.
 	 */
-	if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3))
+	if (++nr_loops > 3) {
+		RB_WARN_ON(cpu_buffer, !failed);
 		return NULL;
+	}
 
 	if (rb_per_cpu_empty(cpu_buffer))
 		return NULL;
@@ -3992,6 +4079,10 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 	}
 
 	event = rb_iter_head_event(iter);
+	if (!event) {
+		failed = true;
+		goto again;
+	}
 
 	switch (event->type_len) {
 	case RINGBUF_TYPE_PADDING:
@@ -4102,6 +4193,20 @@ ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
 	return event;
 }
 
+/** ring_buffer_iter_dropped - report if there are dropped events
+ * @iter: The ring buffer iterator
+ *
+ * Returns true if there was dropped events since the last peek.
+ */
+bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter)
+{
+	bool ret = iter->missed_events != 0;
+
+	iter->missed_events = 0;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_iter_dropped);
+
 /**
  * ring_buffer_iter_peek - peek at the next event to be read
  * @iter: The ring buffer iterator
@@ -4208,16 +4313,21 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags)
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
 		return NULL;
 
-	iter = kmalloc(sizeof(*iter), flags);
+	iter = kzalloc(sizeof(*iter), flags);
 	if (!iter)
 		return NULL;
 
+	iter->event = kmalloc(BUF_MAX_DATA_SIZE, flags);
+	if (!iter->event) {
+		kfree(iter);
+		return NULL;
+	}
+
 	cpu_buffer = buffer->buffers[cpu];
 
 	iter->cpu_buffer = cpu_buffer;
 
-	atomic_inc(&buffer->resize_disabled);
-	atomic_inc(&cpu_buffer->record_disabled);
+	atomic_inc(&cpu_buffer->resize_disabled);
 
 	return iter;
 }
@@ -4290,42 +4400,31 @@ ring_buffer_read_finish(struct ring_buffer_iter *iter)
 	rb_check_pages(cpu_buffer);
 	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
-	atomic_dec(&cpu_buffer->record_disabled);
-	atomic_dec(&cpu_buffer->buffer->resize_disabled);
+	atomic_dec(&cpu_buffer->resize_disabled);
+	kfree(iter->event);
 	kfree(iter);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_finish);
 
 /**
- * ring_buffer_read - read the next item in the ring buffer by the iterator
+ * ring_buffer_iter_advance - advance the iterator to the next location
  * @iter: The ring buffer iterator
- * @ts: The time stamp of the event read.
  *
- * This reads the next event in the ring buffer and increments the iterator.
+ * Move the location of the iterator such that the next read will
+ * be the next location of the iterator.
  */
-struct ring_buffer_event *
-ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
+void ring_buffer_iter_advance(struct ring_buffer_iter *iter)
 {
-	struct ring_buffer_event *event;
 	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- again:
-	event = rb_iter_peek(iter, ts);
-	if (!event)
-		goto out;
-
-	if (event->type_len == RINGBUF_TYPE_PADDING)
-		goto again;
 
 	rb_advance_iter(iter);
- out:
-	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
-	return event;
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 }
-EXPORT_SYMBOL_GPL(ring_buffer_read);
+EXPORT_SYMBOL_GPL(ring_buffer_iter_advance);
 
 /**
  * ring_buffer_size - return the size of the ring buffer (in bytes)
@@ -4406,7 +4505,7 @@ void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu)
 	if (!cpumask_test_cpu(cpu, buffer->cpumask))
 		return;
 
-	atomic_inc(&buffer->resize_disabled);
+	atomic_inc(&cpu_buffer->resize_disabled);
 	atomic_inc(&cpu_buffer->record_disabled);
 
 	/* Make sure all commits have finished */
@@ -4427,7 +4526,7 @@ void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu)
 	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
 	atomic_dec(&cpu_buffer->record_disabled);
-	atomic_dec(&buffer->resize_disabled);
+	atomic_dec(&cpu_buffer->resize_disabled);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6b11e4e2150c..8d2b98812625 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -386,16 +386,22 @@ trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
  * Returns false if @task should be traced.
  */
 bool
-trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
+trace_ignore_this_task(struct trace_pid_list *filtered_pids,
+		       struct trace_pid_list *filtered_no_pids,
+		       struct task_struct *task)
 {
 	/*
-	 * Return false, because if filtered_pids does not exist,
-	 * all pids are good to trace.
+	 * If filterd_no_pids is not empty, and the task's pid is listed
+	 * in filtered_no_pids, then return true.
+	 * Otherwise, if filtered_pids is empty, that means we can
+	 * trace all tasks. If it has content, then only trace pids
+	 * within filtered_pids.
 	 */
-	if (!filtered_pids)
-		return false;
 
-	return !trace_find_filtered_pid(filtered_pids, task->pid);
+	return (filtered_pids &&
+		!trace_find_filtered_pid(filtered_pids, task->pid)) ||
+		(filtered_no_pids &&
+		 trace_find_filtered_pid(filtered_no_pids, task->pid));
 }
 
 /**
@@ -3378,7 +3384,7 @@ static void trace_iterator_increment(struct trace_iterator *iter)
 
 	iter->idx++;
 	if (buf_iter)
-		ring_buffer_read(buf_iter, NULL);
+		ring_buffer_iter_advance(buf_iter);
 }
 
 static struct trace_entry *
@@ -3388,11 +3394,15 @@ peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
 	struct ring_buffer_event *event;
 	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
 
-	if (buf_iter)
+	if (buf_iter) {
 		event = ring_buffer_iter_peek(buf_iter, ts);
-	else
+		if (lost_events)
+			*lost_events = ring_buffer_iter_dropped(buf_iter) ?
+				(unsigned long)-1 : 0;
+	} else {
 		event = ring_buffer_peek(iter->array_buffer->buffer, cpu, ts,
 					 lost_events);
+	}
 
 	if (event) {
 		iter->ent_size = ring_buffer_event_length(event);
@@ -3462,11 +3472,51 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
 	return next;
 }
 
+#define STATIC_TEMP_BUF_SIZE	128
+static char static_temp_buf[STATIC_TEMP_BUF_SIZE];
+
 /* Find the next real entry, without updating the iterator itself */
 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 					  int *ent_cpu, u64 *ent_ts)
 {
-	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
+	/* __find_next_entry will reset ent_size */
+	int ent_size = iter->ent_size;
+	struct trace_entry *entry;
+
+	/*
+	 * If called from ftrace_dump(), then the iter->temp buffer
+	 * will be the static_temp_buf and not created from kmalloc.
+	 * If the entry size is greater than the buffer, we can
+	 * not save it. Just return NULL in that case. This is only
+	 * used to add markers when two consecutive events' time
+	 * stamps have a large delta. See trace_print_lat_context()
+	 */
+	if (iter->temp == static_temp_buf &&
+	    STATIC_TEMP_BUF_SIZE < ent_size)
+		return NULL;
+
+	/*
+	 * The __find_next_entry() may call peek_next_entry(), which may
+	 * call ring_buffer_peek() that may make the contents of iter->ent
+	 * undefined. Need to copy iter->ent now.
+	 */
+	if (iter->ent && iter->ent != iter->temp) {
+		if ((!iter->temp || iter->temp_size < iter->ent_size) &&
+		    !WARN_ON_ONCE(iter->temp == static_temp_buf)) {
+			kfree(iter->temp);
+			iter->temp = kmalloc(iter->ent_size, GFP_KERNEL);
+			if (!iter->temp)
+				return NULL;
+		}
+		memcpy(iter->temp, iter->ent, iter->ent_size);
+		iter->temp_size = iter->ent_size;
+		iter->ent = iter->temp;
+	}
+	entry = __find_next_entry(iter, ent_cpu, NULL, ent_ts);
+	/* Put back the original ent_size */
+	iter->ent_size = ent_size;
+
+	return entry;
 }
 
 /* Find the next real entry, and increment the iterator to the next entry */
@@ -3538,7 +3588,7 @@ void tracing_iter_reset(struct trace_iterator *iter, int cpu)
 		if (ts >= iter->array_buffer->time_start)
 			break;
 		entries++;
-		ring_buffer_read(buf_iter, NULL);
+		ring_buffer_iter_advance(buf_iter);
 	}
 
 	per_cpu_ptr(iter->array_buffer->data, cpu)->skipped_entries = entries;
@@ -3981,8 +4031,12 @@ enum print_line_t print_trace_line(struct trace_iterator *iter)
 	enum print_line_t ret;
 
 	if (iter->lost_events) {
-		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
-				 iter->cpu, iter->lost_events);
+		if (iter->lost_events == (unsigned long)-1)
+			trace_seq_printf(&iter->seq, "CPU:%d [LOST EVENTS]\n",
+					 iter->cpu);
+		else
+			trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+					 iter->cpu, iter->lost_events);
 		if (trace_seq_has_overflowed(&iter->seq))
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
@@ -4198,6 +4252,18 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 		goto release;
 
 	/*
+	 * trace_find_next_entry() may need to save off iter->ent.
+	 * It will place it into the iter->temp buffer. As most
+	 * events are less than 128, allocate a buffer of that size.
+	 * If one is greater, then trace_find_next_entry() will
+	 * allocate a new buffer to adjust for the bigger iter->ent.
+	 * It's not critical if it fails to get allocated here.
+	 */
+	iter->temp = kmalloc(128, GFP_KERNEL);
+	if (iter->temp)
+		iter->temp_size = 128;
+
+	/*
 	 * We make a copy of the current tracer to avoid concurrent
 	 * changes on it while we are reading.
 	 */
@@ -4237,8 +4303,11 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
 	if (trace_clocks[tr->clock_id].in_ns)
 		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
 
-	/* stop the trace while dumping if we are not opening "snapshot" */
-	if (!iter->snapshot)
+	/*
+	 * If pause-on-trace is enabled, then stop the trace while
+	 * dumping, unless this is the "snapshot" file
+	 */
+	if (!iter->snapshot && (tr->trace_flags & TRACE_ITER_PAUSE_ON_TRACE))
 		tracing_stop_tr(tr);
 
 	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
@@ -4269,6 +4338,7 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot)
  fail:
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
+	kfree(iter->temp);
 	kfree(iter->buffer_iter);
 release:
 	seq_release_private(inode, file);
@@ -4334,7 +4404,7 @@ static int tracing_release(struct inode *inode, struct file *file)
 	if (iter->trace && iter->trace->close)
 		iter->trace->close(iter);
 
-	if (!iter->snapshot)
+	if (!iter->snapshot && tr->stop_count)
 		/* reenable tracing if it was previously enabled */
 		tracing_start_tr(tr);
 
@@ -4344,6 +4414,7 @@ static int tracing_release(struct inode *inode, struct file *file)
 
 	mutex_destroy(&iter->mutex);
 	free_cpumask_var(iter->started);
+	kfree(iter->temp);
 	kfree(iter->trace);
 	kfree(iter->buffer_iter);
 	seq_release_private(inode, file);
@@ -4964,6 +5035,8 @@ static const char readme_msg[] =
 #ifdef CONFIG_FUNCTION_TRACER
 	"  set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
 	"\t\t    (function)\n"
+	"  set_ftrace_notrace_pid\t- Write pid(s) to not function trace those pids\n"
+	"\t\t    (function)\n"
 #endif
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	"  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
@@ -9146,6 +9219,9 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
 
 	/* Simulate the iterator */
 	trace_init_global_iter(&iter);
+	/* Can not use kmalloc for iter.temp */
+	iter.temp = static_temp_buf;
+	iter.temp_size = STATIC_TEMP_BUF_SIZE;
 
 	for_each_tracing_cpu(cpu) {
 		atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
@@ -9334,7 +9410,7 @@ __init static int tracer_alloc_buffers(void)
 		goto out_free_buffer_mask;
 
 	/* Only allocate trace_printk buffers if a trace_printk exists */
-	if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+	if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
 		/* Must be called before global_trace.buffer is allocated */
 		trace_printk_init_buffers();
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 99372dd7d168..4eb1d004d5f2 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -178,10 +178,10 @@ struct trace_array_cpu {
 	kuid_t			uid;
 	char			comm[TASK_COMM_LEN];
 
-	bool			ignore_pid;
 #ifdef CONFIG_FUNCTION_TRACER
-	bool			ftrace_ignore_pid;
+	int			ftrace_ignore_pid;
 #endif
+	bool			ignore_pid;
 };
 
 struct tracer;
@@ -207,6 +207,30 @@ struct trace_pid_list {
 	unsigned long			*pids;
 };
 
+enum {
+	TRACE_PIDS		= BIT(0),
+	TRACE_NO_PIDS		= BIT(1),
+};
+
+static inline bool pid_type_enabled(int type, struct trace_pid_list *pid_list,
+				    struct trace_pid_list *no_pid_list)
+{
+	/* Return true if the pid list in type has pids */
+	return ((type & TRACE_PIDS) && pid_list) ||
+		((type & TRACE_NO_PIDS) && no_pid_list);
+}
+
+static inline bool still_need_pid_events(int type, struct trace_pid_list *pid_list,
+					 struct trace_pid_list *no_pid_list)
+{
+	/*
+	 * Turning off what is in @type, return true if the "other"
+	 * pid list, still has pids in it.
+	 */
+	return (!(type & TRACE_PIDS) && pid_list) ||
+		(!(type & TRACE_NO_PIDS) && no_pid_list);
+}
+
 typedef bool (*cond_update_fn_t)(struct trace_array *tr, void *cond_data);
 
 /**
@@ -285,6 +309,7 @@ struct trace_array {
 #endif
 #endif
 	struct trace_pid_list	__rcu *filtered_pids;
+	struct trace_pid_list	__rcu *filtered_no_pids;
 	/*
 	 * max_lock is used to protect the swapping of buffers
 	 * when taking a max snapshot. The buffers themselves are
@@ -331,6 +356,7 @@ struct trace_array {
 #ifdef CONFIG_FUNCTION_TRACER
 	struct ftrace_ops	*ops;
 	struct trace_pid_list	__rcu *function_pids;
+	struct trace_pid_list	__rcu *function_no_pids;
 #ifdef CONFIG_DYNAMIC_FTRACE
 	/* All of these are protected by the ftrace_lock */
 	struct list_head	func_probes;
@@ -557,12 +583,7 @@ struct tracer {
  * caller, and we can skip the current check.
  */
 enum {
-	TRACE_BUFFER_BIT,
-	TRACE_BUFFER_NMI_BIT,
-	TRACE_BUFFER_IRQ_BIT,
-	TRACE_BUFFER_SIRQ_BIT,
-
-	/* Start of function recursion bits */
+	/* Function recursion bits */
 	TRACE_FTRACE_BIT,
 	TRACE_FTRACE_NMI_BIT,
 	TRACE_FTRACE_IRQ_BIT,
@@ -787,6 +808,7 @@ extern int pid_max;
 bool trace_find_filtered_pid(struct trace_pid_list *filtered_pids,
 			     pid_t search_pid);
 bool trace_ignore_this_task(struct trace_pid_list *filtered_pids,
+			    struct trace_pid_list *filtered_no_pids,
 			    struct task_struct *task);
 void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
 				  struct task_struct *self,
@@ -1307,6 +1329,7 @@ extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 		C(IRQ_INFO,		"irq-info"),		\
 		C(MARKERS,		"markers"),		\
 		C(EVENT_FORK,		"event-fork"),		\
+		C(PAUSE_ON_TRACE,	"pause-on-trace"),	\
 		FUNCTION_FLAGS					\
 		FGRAPH_FLAGS					\
 		STACK_FLAGS					\
diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h
index f22746f3c132..a523da0dae0a 100644
--- a/kernel/trace/trace_entries.h
+++ b/kernel/trace/trace_entries.h
@@ -325,14 +325,16 @@ FTRACE_ENTRY(hwlat, hwlat_entry,
 		__field_desc(	long,	timestamp,	tv_nsec		)
 		__field(	unsigned int,		nmi_count	)
 		__field(	unsigned int,		seqnum		)
+		__field(	unsigned int,		count		)
 	),
 
-	F_printk("cnt:%u\tts:%010llu.%010lu\tinner:%llu\touter:%llu\tnmi-ts:%llu\tnmi-count:%u\n",
+	F_printk("cnt:%u\tts:%010llu.%010lu\tinner:%llu\touter:%llu\tcount:%d\tnmi-ts:%llu\tnmi-count:%u\n",
 		 __entry->seqnum,
 		 __entry->tv_sec,
 		 __entry->tv_nsec,
 		 __entry->duration,
 		 __entry->outer_duration,
+		 __entry->count,
 		 __entry->nmi_total_ts,
 		 __entry->nmi_count)
 );
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index f38234ecea18..242f59e7f17d 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -232,10 +232,13 @@ bool trace_event_ignore_this_pid(struct trace_event_file *trace_file)
 {
 	struct trace_array *tr = trace_file->tr;
 	struct trace_array_cpu *data;
+	struct trace_pid_list *no_pid_list;
 	struct trace_pid_list *pid_list;
 
 	pid_list = rcu_dereference_raw(tr->filtered_pids);
-	if (!pid_list)
+	no_pid_list = rcu_dereference_raw(tr->filtered_no_pids);
+
+	if (!pid_list && !no_pid_list)
 		return false;
 
 	data = this_cpu_ptr(tr->array_buffer.data);
@@ -510,6 +513,9 @@ event_filter_pid_sched_process_exit(void *data, struct task_struct *task)
 
 	pid_list = rcu_dereference_raw(tr->filtered_pids);
 	trace_filter_add_remove_task(pid_list, NULL, task);
+
+	pid_list = rcu_dereference_raw(tr->filtered_no_pids);
+	trace_filter_add_remove_task(pid_list, NULL, task);
 }
 
 static void
@@ -522,6 +528,9 @@ event_filter_pid_sched_process_fork(void *data,
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
 	trace_filter_add_remove_task(pid_list, self, task);
+
+	pid_list = rcu_dereference_sched(tr->filtered_no_pids);
+	trace_filter_add_remove_task(pid_list, self, task);
 }
 
 void trace_event_follow_fork(struct trace_array *tr, bool enable)
@@ -544,13 +553,23 @@ event_filter_pid_sched_switch_probe_pre(void *data, bool preempt,
 		    struct task_struct *prev, struct task_struct *next)
 {
 	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
 	struct trace_pid_list *pid_list;
+	bool ret;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
-	this_cpu_write(tr->array_buffer.data->ignore_pid,
-		       trace_ignore_this_task(pid_list, prev) &&
-		       trace_ignore_this_task(pid_list, next));
+	/*
+	 * Sched switch is funny, as we only want to ignore it
+	 * in the notrace case if both prev and next should be ignored.
+	 */
+	ret = trace_ignore_this_task(NULL, no_pid_list, prev) &&
+		trace_ignore_this_task(NULL, no_pid_list, next);
+
+	this_cpu_write(tr->array_buffer.data->ignore_pid, ret ||
+		       (trace_ignore_this_task(pid_list, NULL, prev) &&
+			trace_ignore_this_task(pid_list, NULL, next)));
 }
 
 static void
@@ -558,18 +577,21 @@ event_filter_pid_sched_switch_probe_post(void *data, bool preempt,
 		    struct task_struct *prev, struct task_struct *next)
 {
 	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
 	struct trace_pid_list *pid_list;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
 	this_cpu_write(tr->array_buffer.data->ignore_pid,
-		       trace_ignore_this_task(pid_list, next));
+		       trace_ignore_this_task(pid_list, no_pid_list, next));
 }
 
 static void
 event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 {
 	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
 	struct trace_pid_list *pid_list;
 
 	/* Nothing to do if we are already tracing */
@@ -577,15 +599,17 @@ event_filter_pid_sched_wakeup_probe_pre(void *data, struct task_struct *task)
 		return;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
 	this_cpu_write(tr->array_buffer.data->ignore_pid,
-		       trace_ignore_this_task(pid_list, task));
+		       trace_ignore_this_task(pid_list, no_pid_list, task));
 }
 
 static void
 event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 {
 	struct trace_array *tr = data;
+	struct trace_pid_list *no_pid_list;
 	struct trace_pid_list *pid_list;
 
 	/* Nothing to do if we are not tracing */
@@ -593,23 +617,15 @@ event_filter_pid_sched_wakeup_probe_post(void *data, struct task_struct *task)
 		return;
 
 	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	no_pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
 	/* Set tracing if current is enabled */
 	this_cpu_write(tr->array_buffer.data->ignore_pid,
-		       trace_ignore_this_task(pid_list, current));
+		       trace_ignore_this_task(pid_list, no_pid_list, current));
 }
 
-static void __ftrace_clear_event_pids(struct trace_array *tr)
+static void unregister_pid_events(struct trace_array *tr)
 {
-	struct trace_pid_list *pid_list;
-	struct trace_event_file *file;
-	int cpu;
-
-	pid_list = rcu_dereference_protected(tr->filtered_pids,
-					     lockdep_is_held(&event_mutex));
-	if (!pid_list)
-		return;
-
 	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_pre, tr);
 	unregister_trace_sched_switch(event_filter_pid_sched_switch_probe_post, tr);
 
@@ -621,26 +637,55 @@ static void __ftrace_clear_event_pids(struct trace_array *tr)
 
 	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_pre, tr);
 	unregister_trace_sched_waking(event_filter_pid_sched_wakeup_probe_post, tr);
+}
 
-	list_for_each_entry(file, &tr->events, list) {
-		clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
+static void __ftrace_clear_event_pids(struct trace_array *tr, int type)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
+	struct trace_event_file *file;
+	int cpu;
+
+	pid_list = rcu_dereference_protected(tr->filtered_pids,
+					     lockdep_is_held(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     lockdep_is_held(&event_mutex));
+
+	/* Make sure there's something to do */
+	if (!pid_type_enabled(type, pid_list, no_pid_list))
+		return;
+
+	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
+		unregister_pid_events(tr);
+
+		list_for_each_entry(file, &tr->events, list) {
+			clear_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
+		}
+
+		for_each_possible_cpu(cpu)
+			per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
 	}
 
-	for_each_possible_cpu(cpu)
-		per_cpu_ptr(tr->array_buffer.data, cpu)->ignore_pid = false;
+	if (type & TRACE_PIDS)
+		rcu_assign_pointer(tr->filtered_pids, NULL);
 
-	rcu_assign_pointer(tr->filtered_pids, NULL);
+	if (type & TRACE_NO_PIDS)
+		rcu_assign_pointer(tr->filtered_no_pids, NULL);
 
 	/* Wait till all users are no longer using pid filtering */
 	tracepoint_synchronize_unregister();
 
-	trace_free_pid_list(pid_list);
+	if ((type & TRACE_PIDS) && pid_list)
+		trace_free_pid_list(pid_list);
+
+	if ((type & TRACE_NO_PIDS) && no_pid_list)
+		trace_free_pid_list(no_pid_list);
 }
 
-static void ftrace_clear_event_pids(struct trace_array *tr)
+static void ftrace_clear_event_pids(struct trace_array *tr, int type)
 {
 	mutex_lock(&event_mutex);
-	__ftrace_clear_event_pids(tr);
+	__ftrace_clear_event_pids(tr, type);
 	mutex_unlock(&event_mutex);
 }
 
@@ -1013,15 +1058,32 @@ static void t_stop(struct seq_file *m, void *p)
 }
 
 static void *
-p_next(struct seq_file *m, void *v, loff_t *pos)
+__next(struct seq_file *m, void *v, loff_t *pos, int type)
 {
 	struct trace_array *tr = m->private;
-	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->filtered_pids);
+	struct trace_pid_list *pid_list;
+
+	if (type == TRACE_PIDS)
+		pid_list = rcu_dereference_sched(tr->filtered_pids);
+	else
+		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
 	return trace_pid_next(pid_list, v, pos);
 }
 
-static void *p_start(struct seq_file *m, loff_t *pos)
+static void *
+p_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return __next(m, v, pos, TRACE_PIDS);
+}
+
+static void *
+np_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return __next(m, v, pos, TRACE_NO_PIDS);
+}
+
+static void *__start(struct seq_file *m, loff_t *pos, int type)
 	__acquires(RCU)
 {
 	struct trace_pid_list *pid_list;
@@ -1036,7 +1098,10 @@ static void *p_start(struct seq_file *m, loff_t *pos)
 	mutex_lock(&event_mutex);
 	rcu_read_lock_sched();
 
-	pid_list = rcu_dereference_sched(tr->filtered_pids);
+	if (type == TRACE_PIDS)
+		pid_list = rcu_dereference_sched(tr->filtered_pids);
+	else
+		pid_list = rcu_dereference_sched(tr->filtered_no_pids);
 
 	if (!pid_list)
 		return NULL;
@@ -1044,6 +1109,18 @@ static void *p_start(struct seq_file *m, loff_t *pos)
 	return trace_pid_start(pid_list, pos);
 }
 
+static void *p_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	return __start(m, pos, TRACE_PIDS);
+}
+
+static void *np_start(struct seq_file *m, loff_t *pos)
+	__acquires(RCU)
+{
+	return __start(m, pos, TRACE_NO_PIDS);
+}
+
 static void p_stop(struct seq_file *m, void *p)
 	__releases(RCU)
 {
@@ -1588,6 +1665,7 @@ static void ignore_task_cpu(void *data)
 {
 	struct trace_array *tr = data;
 	struct trace_pid_list *pid_list;
+	struct trace_pid_list *no_pid_list;
 
 	/*
 	 * This function is called by on_each_cpu() while the
@@ -1595,18 +1673,50 @@ static void ignore_task_cpu(void *data)
 	 */
 	pid_list = rcu_dereference_protected(tr->filtered_pids,
 					     mutex_is_locked(&event_mutex));
+	no_pid_list = rcu_dereference_protected(tr->filtered_no_pids,
+					     mutex_is_locked(&event_mutex));
 
 	this_cpu_write(tr->array_buffer.data->ignore_pid,
-		       trace_ignore_this_task(pid_list, current));
+		       trace_ignore_this_task(pid_list, no_pid_list, current));
+}
+
+static void register_pid_events(struct trace_array *tr)
+{
+	/*
+	 * Register a probe that is called before all other probes
+	 * to set ignore_pid if next or prev do not match.
+	 * Register a probe this is called after all other probes
+	 * to only keep ignore_pid set if next pid matches.
+	 */
+	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
+					 tr, 0);
+
+	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
+					 tr, 0);
+
+	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
+					     tr, INT_MAX);
+	register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
+					     tr, 0);
+
+	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
+					 tr, INT_MAX);
+	register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
+					 tr, 0);
 }
 
 static ssize_t
-ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
-		       size_t cnt, loff_t *ppos)
+event_pid_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos, int type)
 {
 	struct seq_file *m = filp->private_data;
 	struct trace_array *tr = m->private;
 	struct trace_pid_list *filtered_pids = NULL;
+	struct trace_pid_list *other_pids = NULL;
 	struct trace_pid_list *pid_list;
 	struct trace_event_file *file;
 	ssize_t ret;
@@ -1620,14 +1730,26 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
 
 	mutex_lock(&event_mutex);
 
-	filtered_pids = rcu_dereference_protected(tr->filtered_pids,
-					     lockdep_is_held(&event_mutex));
+	if (type == TRACE_PIDS) {
+		filtered_pids = rcu_dereference_protected(tr->filtered_pids,
+							  lockdep_is_held(&event_mutex));
+		other_pids = rcu_dereference_protected(tr->filtered_no_pids,
+							  lockdep_is_held(&event_mutex));
+	} else {
+		filtered_pids = rcu_dereference_protected(tr->filtered_no_pids,
+							  lockdep_is_held(&event_mutex));
+		other_pids = rcu_dereference_protected(tr->filtered_pids,
+							  lockdep_is_held(&event_mutex));
+	}
 
 	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
 	if (ret < 0)
 		goto out;
 
-	rcu_assign_pointer(tr->filtered_pids, pid_list);
+	if (type == TRACE_PIDS)
+		rcu_assign_pointer(tr->filtered_pids, pid_list);
+	else
+		rcu_assign_pointer(tr->filtered_no_pids, pid_list);
 
 	list_for_each_entry(file, &tr->events, list) {
 		set_bit(EVENT_FILE_FL_PID_FILTER_BIT, &file->flags);
@@ -1636,32 +1758,8 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
 	if (filtered_pids) {
 		tracepoint_synchronize_unregister();
 		trace_free_pid_list(filtered_pids);
-	} else if (pid_list) {
-		/*
-		 * Register a probe that is called before all other probes
-		 * to set ignore_pid if next or prev do not match.
-		 * Register a probe this is called after all other probes
-		 * to only keep ignore_pid set if next pid matches.
-		 */
-		register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_pre,
-						 tr, INT_MAX);
-		register_trace_prio_sched_switch(event_filter_pid_sched_switch_probe_post,
-						 tr, 0);
-
-		register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_pre,
-						 tr, INT_MAX);
-		register_trace_prio_sched_wakeup(event_filter_pid_sched_wakeup_probe_post,
-						 tr, 0);
-
-		register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_pre,
-						     tr, INT_MAX);
-		register_trace_prio_sched_wakeup_new(event_filter_pid_sched_wakeup_probe_post,
-						     tr, 0);
-
-		register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_pre,
-						 tr, INT_MAX);
-		register_trace_prio_sched_waking(event_filter_pid_sched_wakeup_probe_post,
-						 tr, 0);
+	} else if (pid_list && !other_pids) {
+		register_pid_events(tr);
 	}
 
 	/*
@@ -1680,9 +1778,24 @@ ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
 	return ret;
 }
 
+static ssize_t
+ftrace_event_pid_write(struct file *filp, const char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
+}
+
+static ssize_t
+ftrace_event_npid_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	return event_pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
+}
+
 static int ftrace_event_avail_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_open(struct inode *inode, struct file *file);
 static int ftrace_event_set_pid_open(struct inode *inode, struct file *file);
+static int ftrace_event_set_npid_open(struct inode *inode, struct file *file);
 static int ftrace_event_release(struct inode *inode, struct file *file);
 
 static const struct seq_operations show_event_seq_ops = {
@@ -1706,6 +1819,13 @@ static const struct seq_operations show_set_pid_seq_ops = {
 	.stop = p_stop,
 };
 
+static const struct seq_operations show_set_no_pid_seq_ops = {
+	.start = np_start,
+	.next = np_next,
+	.show = trace_pid_show,
+	.stop = p_stop,
+};
+
 static const struct file_operations ftrace_avail_fops = {
 	.open = ftrace_event_avail_open,
 	.read = seq_read,
@@ -1729,6 +1849,14 @@ static const struct file_operations ftrace_set_event_pid_fops = {
 	.release = ftrace_event_release,
 };
 
+static const struct file_operations ftrace_set_event_notrace_pid_fops = {
+	.open = ftrace_event_set_npid_open,
+	.read = seq_read,
+	.write = ftrace_event_npid_write,
+	.llseek = seq_lseek,
+	.release = ftrace_event_release,
+};
+
 static const struct file_operations ftrace_enable_fops = {
 	.open = tracing_open_generic,
 	.read = event_enable_read,
@@ -1858,7 +1986,28 @@ ftrace_event_set_pid_open(struct inode *inode, struct file *file)
 
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
-		ftrace_clear_event_pids(tr);
+		ftrace_clear_event_pids(tr, TRACE_PIDS);
+
+	ret = ftrace_event_open(inode, file, seq_ops);
+	if (ret < 0)
+		trace_array_put(tr);
+	return ret;
+}
+
+static int
+ftrace_event_set_npid_open(struct inode *inode, struct file *file)
+{
+	const struct seq_operations *seq_ops = &show_set_no_pid_seq_ops;
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	ret = tracing_check_open_get_tr(tr);
+	if (ret)
+		return ret;
+
+	if ((file->f_mode & FMODE_WRITE) &&
+	    (file->f_flags & O_TRUNC))
+		ftrace_clear_event_pids(tr, TRACE_NO_PIDS);
 
 	ret = ftrace_event_open(inode, file, seq_ops);
 	if (ret < 0)
@@ -3075,6 +3224,11 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr)
 	if (!entry)
 		pr_warn("Could not create tracefs 'set_event_pid' entry\n");
 
+	entry = tracefs_create_file("set_event_notrace_pid", 0644, parent,
+				    tr, &ftrace_set_event_notrace_pid_fops);
+	if (!entry)
+		pr_warn("Could not create tracefs 'set_event_notrace_pid' entry\n");
+
 	/* ring buffer internal formats */
 	entry = trace_create_file("header_page", 0444, d_events,
 				  ring_buffer_print_page_header,
@@ -3158,7 +3312,7 @@ int event_trace_del_tracer(struct trace_array *tr)
 	clear_event_triggers(tr);
 
 	/* Clear the pid list */
-	__ftrace_clear_event_pids(tr);
+	__ftrace_clear_event_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
 
 	/* Disable any running events */
 	__ftrace_set_clr_event_nolock(tr, NULL, NULL, NULL, 0);
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 7d71546ba00a..4a9c49c08ec9 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -482,7 +482,7 @@ get_return_for_leaf(struct trace_iterator *iter,
 
 	/* this is a leaf, now advance the iterator */
 	if (ring_iter)
-		ring_buffer_read(ring_iter, NULL);
+		ring_buffer_iter_advance(ring_iter);
 
 	return next;
 }
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index a48808c43249..e2be7bb7ef7e 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -83,6 +83,7 @@ struct hwlat_sample {
 	u64			nmi_total_ts;	/* Total time spent in NMIs */
 	struct timespec64	timestamp;	/* wall time */
 	int			nmi_count;	/* # NMIs during this sample */
+	int			count;		/* # of iteratons over threash */
 };
 
 /* keep the global state somewhere. */
@@ -124,6 +125,7 @@ static void trace_hwlat_sample(struct hwlat_sample *sample)
 	entry->timestamp		= sample->timestamp;
 	entry->nmi_total_ts		= sample->nmi_total_ts;
 	entry->nmi_count		= sample->nmi_count;
+	entry->count			= sample->count;
 
 	if (!call_filter_check_discard(call, entry, buffer, event))
 		trace_buffer_unlock_commit_nostack(buffer, event);
@@ -167,12 +169,14 @@ void trace_hwlat_callback(bool enter)
 static int get_sample(void)
 {
 	struct trace_array *tr = hwlat_trace;
+	struct hwlat_sample s;
 	time_type start, t1, t2, last_t2;
-	s64 diff, total, last_total = 0;
+	s64 diff, outer_diff, total, last_total = 0;
 	u64 sample = 0;
 	u64 thresh = tracing_thresh;
 	u64 outer_sample = 0;
 	int ret = -1;
+	unsigned int count = 0;
 
 	do_div(thresh, NSEC_PER_USEC); /* modifies interval value */
 
@@ -186,6 +190,7 @@ static int get_sample(void)
 
 	init_time(last_t2, 0);
 	start = time_get(); /* start timestamp */
+	outer_diff = 0;
 
 	do {
 
@@ -194,14 +199,14 @@ static int get_sample(void)
 
 		if (time_u64(last_t2)) {
 			/* Check the delta from outer loop (t2 to next t1) */
-			diff = time_to_us(time_sub(t1, last_t2));
+			outer_diff = time_to_us(time_sub(t1, last_t2));
 			/* This shouldn't happen */
-			if (diff < 0) {
+			if (outer_diff < 0) {
 				pr_err(BANNER "time running backwards\n");
 				goto out;
 			}
-			if (diff > outer_sample)
-				outer_sample = diff;
+			if (outer_diff > outer_sample)
+				outer_sample = outer_diff;
 		}
 		last_t2 = t2;
 
@@ -217,6 +222,12 @@ static int get_sample(void)
 		/* This checks the inner loop (t1 to t2) */
 		diff = time_to_us(time_sub(t2, t1));     /* current diff */
 
+		if (diff > thresh || outer_diff > thresh) {
+			if (!count)
+				ktime_get_real_ts64(&s.timestamp);
+			count++;
+		}
+
 		/* This shouldn't happen */
 		if (diff < 0) {
 			pr_err(BANNER "time running backwards\n");
@@ -236,7 +247,6 @@ static int get_sample(void)
 
 	/* If we exceed the threshold value, we have found a hardware latency */
 	if (sample > thresh || outer_sample > thresh) {
-		struct hwlat_sample s;
 		u64 latency;
 
 		ret = 1;
@@ -249,9 +259,9 @@ static int get_sample(void)
 		s.seqnum = hwlat_data.count;
 		s.duration = sample;
 		s.outer_duration = outer_sample;
-		ktime_get_real_ts64(&s.timestamp);
 		s.nmi_total_ts = nmi_total_ts;
 		s.nmi_count = nmi_count;
+		s.count = count;
 		trace_hwlat_sample(&s);
 
 		latency = max(sample, outer_sample);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 362cca52f5de..d0568af4a0ef 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1078,6 +1078,8 @@ static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
 	int i;
 
 	seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
+	if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
+		seq_printf(m, "%d", tk->rp.maxactive);
 	seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
 				trace_probe_name(&tk->tp));
 
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b4909082f6a4..9a121e147102 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -617,22 +617,19 @@ int trace_print_context(struct trace_iterator *iter)
 
 int trace_print_lat_context(struct trace_iterator *iter)
 {
+	struct trace_entry *entry, *next_entry;
 	struct trace_array *tr = iter->tr;
-	/* trace_find_next_entry will reset ent_size */
-	int ent_size = iter->ent_size;
 	struct trace_seq *s = &iter->seq;
-	u64 next_ts;
-	struct trace_entry *entry = iter->ent,
-			   *next_entry = trace_find_next_entry(iter, NULL,
-							       &next_ts);
 	unsigned long verbose = (tr->trace_flags & TRACE_ITER_VERBOSE);
+	u64 next_ts;
 
-	/* Restore the original ent_size */
-	iter->ent_size = ent_size;
-
+	next_entry = trace_find_next_entry(iter, NULL, &next_ts);
 	if (!next_entry)
 		next_ts = iter->ts;
 
+	/* trace_find_next_entry() may change iter->ent */
+	entry = iter->ent;
+
 	if (verbose) {
 		char comm[TASK_COMM_LEN];
 
@@ -1158,12 +1155,12 @@ trace_hwlat_print(struct trace_iterator *iter, int flags,
 
 	trace_assign_type(field, entry);
 
-	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld",
+	trace_seq_printf(s, "#%-5u inner/outer(us): %4llu/%-5llu ts:%lld.%09ld count:%d",
 			 field->seqnum,
 			 field->duration,
 			 field->outer_duration,
 			 (long long)field->timestamp.tv_sec,
-			 field->timestamp.tv_nsec);
+			 field->timestamp.tv_nsec, field->count);
 
 	if (field->nmi_count) {
 		/*