Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

7 files changed, 102 insertions, 55 deletions

diff --git a/kernel/kernel/trace/Makefile b/kernel/kernel/trace/Makefile
index 3bbaea068..bc08c6730 100644
--- a/kernel/kernel/trace/Makefile
+++ b/kernel/kernel/trace/Makefile
@@ -1,4 +1,8 @@
 
+# We are fully aware of the dangers of __builtin_return_address()
+FRAME_CFLAGS := $(call cc-disable-warning,frame-address)
+KBUILD_CFLAGS += $(FRAME_CFLAGS)
+
 # Do not instrument the tracer itself:
 
 ifdef CONFIG_FUNCTION_TRACER
diff --git a/kernel/kernel/trace/ring_buffer.c b/kernel/kernel/trace/ring_buffer.c
index 9c6045a27..acbb0e73d 100644
--- a/kernel/kernel/trace/ring_buffer.c
+++ b/kernel/kernel/trace/ring_buffer.c
@@ -437,7 +437,7 @@ struct ring_buffer_per_cpu {
 	raw_spinlock_t			reader_lock;	/* serialize readers */
 	arch_spinlock_t			lock;
 	struct lock_class_key		lock_key;
-	unsigned int			nr_pages;
+	unsigned long			nr_pages;
 	unsigned int			current_context;
 	struct list_head		*pages;
 	struct buffer_page		*head_page;	/* read from head */
@@ -458,7 +458,7 @@ struct ring_buffer_per_cpu {
 	u64				write_stamp;
 	u64				read_stamp;
 	/* ring buffer pages to update, > 0 to add, < 0 to remove */
-	int				nr_pages_to_update;
+	long				nr_pages_to_update;
 	struct list_head		new_pages; /* new pages to add */
 	struct work_struct		update_pages_work;
 	struct completion		update_done;
@@ -1137,10 +1137,10 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
 	return 0;
 }
 
-static int __rb_allocate_pages(int nr_pages, struct list_head *pages, int cpu)
+static int __rb_allocate_pages(long nr_pages, struct list_head *pages, int cpu)
 {
-	int i;
 	struct buffer_page *bpage, *tmp;
+	long i;
 
 	for (i = 0; i < nr_pages; i++) {
 		struct page *page;
@@ -1177,7 +1177,7 @@ free_pages:
 }
 
 static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
-			     unsigned nr_pages)
+			     unsigned long nr_pages)
 {
 	LIST_HEAD(pages);
 
@@ -1202,7 +1202,7 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
 }
 
 static struct ring_buffer_per_cpu *
-rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
+rb_allocate_cpu_buffer(struct ring_buffer *buffer, long nr_pages, int cpu)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
 	struct buffer_page *bpage;
@@ -1302,8 +1302,9 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
 					struct lock_class_key *key)
 {
 	struct ring_buffer *buffer;
+	long nr_pages;
 	int bsize;
-	int cpu, nr_pages;
+	int cpu;
 
 	/* keep it in its own cache line */
 	buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
@@ -1429,12 +1430,12 @@ static inline unsigned long rb_page_write(struct buffer_page *bpage)
 }
 
 static int
-rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned int nr_pages)
+rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned long nr_pages)
 {
 	struct list_head *tail_page, *to_remove, *next_page;
 	struct buffer_page *to_remove_page, *tmp_iter_page;
 	struct buffer_page *last_page, *first_page;
-	unsigned int nr_removed;
+	unsigned long nr_removed;
 	unsigned long head_bit;
 	int page_entries;
 
@@ -1651,7 +1652,7 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
 			int cpu_id)
 {
 	struct ring_buffer_per_cpu *cpu_buffer;
-	unsigned nr_pages;
+	unsigned long nr_pages;
 	int cpu, err = 0;
 
 	/*
@@ -1665,14 +1666,13 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
 	    !cpumask_test_cpu(cpu_id, buffer->cpumask))
 		return size;
 
-	size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
-	size *= BUF_PAGE_SIZE;
+	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
 
 	/* we need a minimum of two pages */
-	if (size < BUF_PAGE_SIZE * 2)
-		size = BUF_PAGE_SIZE * 2;
+	if (nr_pages < 2)
+		nr_pages = 2;
 
-	nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+	size = nr_pages * BUF_PAGE_SIZE;
 
 	/*
 	 * Don't succeed if resizing is disabled, as a reader might be
@@ -4645,8 +4645,9 @@ static int rb_cpu_notify(struct notifier_block *self,
 	struct ring_buffer *buffer =
 		container_of(self, struct ring_buffer, cpu_notify);
 	long cpu = (long)hcpu;
-	int cpu_i, nr_pages_same;
-	unsigned int nr_pages;
+	long nr_pages_same;
+	int cpu_i;
+	unsigned long nr_pages;
 
 	switch (action) {
 	case CPU_UP_PREPARE:
diff --git a/kernel/kernel/trace/trace.c b/kernel/kernel/trace/trace.c
index f1ee84b00..cad1a28bf 100644
--- a/kernel/kernel/trace/trace.c
+++ b/kernel/kernel/trace/trace.c
@@ -2559,17 +2559,17 @@ get_total_entries(struct trace_buffer *buf,
 
 static void print_lat_help_header(struct seq_file *m)
 {
-	seq_puts(m, "#                   _--------=> CPU#              \n"
-		    "#                  / _-------=> irqs-off          \n"
-		    "#                 | / _------=> need-resched      \n"
-		    "#                 || / _-----=> need-resched_lazy \n"
-		    "#                 ||| / _----=> hardirq/softirq   \n"
-		    "#                 |||| / _---=> preempt-depth     \n"
-		    "#                 ||||| / _--=> preempt-lazy-depth\n"
-		    "#                 |||||| / _-=> migrate-disable   \n"
-		    "#                 ||||||| /     delay             \n"
-		    "#  cmd     pid    |||||||| time  |   caller       \n"
-		    "#     \\   /      ||||||||  \\   |   /            \n");
+	seq_puts(m, "#                  _--------=> CPU#              \n"
+		    "#                 / _-------=> irqs-off          \n"
+		    "#                | / _------=> need-resched      \n"
+		    "#                || / _-----=> need-resched_lazy \n"
+		    "#                ||| / _----=> hardirq/softirq   \n"
+		    "#                |||| / _---=> preempt-depth     \n"
+		    "#                ||||| / _--=> preempt-lazy-depth\n"
+		    "#                |||||| / _-=> migrate-disable   \n"
+		    "#                ||||||| /     delay             \n"
+		    "# cmd     pid    |||||||| time   |  caller       \n"
+		    "#     \\   /      ||||||||   \\    |  /            \n");
 }
 
 static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
@@ -2598,11 +2598,11 @@ static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file
 		    "#                            |/  _-----=> need-resched_lazy\n"
 		    "#                            || / _---=> hardirq/softirq\n"
 		    "#                            ||| / _--=> preempt-depth\n"
-		    "#                            |||| /_--=> preempt-lazy-depth\n"
-		    "#                            |||||  _-=> migrate-disable   \n"
-		    "#                            ||||| /    delay\n"
-		    "#           TASK-PID   CPU#  ||||||    TIMESTAMP  FUNCTION\n"
-		    "#              | |       |   ||||||       |         |\n");
+		    "#                            |||| / _-=> preempt-lazy-depth\n"
+		    "#                            ||||| / _-=> migrate-disable   \n"
+		    "#                            |||||| /    delay\n"
+		    "#           TASK-PID   CPU#  |||||||   TIMESTAMP  FUNCTION\n"
+		    "#              | |       |   |||||||      |         |\n");
 }
 
 void
@@ -4737,19 +4737,20 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 	struct trace_iterator *iter = filp->private_data;
 	ssize_t sret;
 
-	/* return any leftover data */
-	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
-	if (sret != -EBUSY)
-		return sret;
-
-	trace_seq_init(&iter->seq);
-
 	/*
 	 * Avoid more than one consumer on a single file descriptor
 	 * This is just a matter of traces coherency, the ring buffer itself
 	 * is protected.
 	 */
 	mutex_lock(&iter->mutex);
+
+	/* return any leftover data */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (sret != -EBUSY)
+		goto out;
+
+	trace_seq_init(&iter->seq);
+
 	if (iter->trace->read) {
 		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
 		if (sret)
@@ -4959,7 +4960,10 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 
 	spd.nr_pages = i;
 
-	ret = splice_to_pipe(pipe, &spd);
+	if (i)
+		ret = splice_to_pipe(pipe, &spd);
+	else
+		ret = 0;
 out:
 	splice_shrink_spd(&spd);
 	return ret;
@@ -5773,9 +5777,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		return -EBUSY;
 #endif
 
-	if (splice_grow_spd(pipe, &spd))
-		return -ENOMEM;
-
 	if (*ppos & (PAGE_SIZE - 1))
 		return -EINVAL;
 
@@ -5785,6 +5786,9 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		len &= PAGE_MASK;
 	}
 
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
  again:
 	trace_access_lock(iter->cpu_file);
 	entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
@@ -5842,19 +5846,21 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 	/* did we read anything? */
 	if (!spd.nr_pages) {
 		if (ret)
-			return ret;
+			goto out;
 
+		ret = -EAGAIN;
 		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
-			return -EAGAIN;
+			goto out;
 
 		ret = wait_on_pipe(iter, true);
 		if (ret)
-			return ret;
+			goto out;
 
 		goto again;
 	}
 
 	ret = splice_to_pipe(pipe, &spd);
+out:
 	splice_shrink_spd(&spd);
 
 	return ret;
diff --git a/kernel/kernel/trace/trace_events.c b/kernel/kernel/trace/trace_events.c
index 0e508e99b..5bd79b347 100644
--- a/kernel/kernel/trace/trace_events.c
+++ b/kernel/kernel/trace/trace_events.c
@@ -246,6 +246,14 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
 
 	local_save_flags(fbuffer->flags);
 	fbuffer->pc = preempt_count();
+	/*
+	 * If CONFIG_PREEMPT is enabled, then the tracepoint itself disables
+	 * preemption (adding one to the preempt_count). Since we are
+	 * interested in the preempt_count at the time the tracepoint was
+	 * hit, we need to subtract one to offset the increment.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT))
+		fbuffer->pc--;
 	fbuffer->trace_file = trace_file;
 
 	fbuffer->event =
@@ -2109,8 +2117,13 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file)
 	trace_create_file("filter", 0644, file->dir, file,
 			  &ftrace_event_filter_fops);
 
-	trace_create_file("trigger", 0644, file->dir, file,
-			  &event_trigger_fops);
+	/*
+	 * Only event directories that can be enabled should have
+	 * triggers.
+	 */
+	if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE))
+		trace_create_file("trigger", 0644, file->dir, file,
+				  &event_trigger_fops);
 
 	trace_create_file("format", 0444, file->dir, call,
 			  &ftrace_event_format_fops);
diff --git a/kernel/kernel/trace/trace_functions_graph.c b/kernel/kernel/trace/trace_functions_graph.c
index a663cbb84..7fd6f5a26 100644
--- a/kernel/kernel/trace/trace_functions_graph.c
+++ b/kernel/kernel/trace/trace_functions_graph.c
@@ -780,6 +780,10 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 
+		/* If a graph tracer ignored set_graph_notrace */
+		if (call->depth < -1)
+			call->depth += FTRACE_NOTRACE_DEPTH;
+
 		/*
 		 * Comments display at + 1 to depth. Since
 		 * this is a leaf function, keep the comments
@@ -788,7 +792,8 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 		cpu_data->depth = call->depth - 1;
 
 		/* No need to keep this function around for this depth */
-		if (call->depth < FTRACE_RETFUNC_DEPTH)
+		if (call->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(call->depth < 0))
 			cpu_data->enter_funcs[call->depth] = 0;
 	}
 
@@ -818,11 +823,16 @@ print_graph_entry_nested(struct trace_iterator *iter,
 		struct fgraph_cpu_data *cpu_data;
 		int cpu = iter->cpu;
 
+		/* If a graph tracer ignored set_graph_notrace */
+		if (call->depth < -1)
+			call->depth += FTRACE_NOTRACE_DEPTH;
+
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 		cpu_data->depth = call->depth;
 
 		/* Save this function pointer to see if the exit matches */
-		if (call->depth < FTRACE_RETFUNC_DEPTH)
+		if (call->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(call->depth < 0))
 			cpu_data->enter_funcs[call->depth] = call->func;
 	}
 
@@ -1052,7 +1062,8 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		 */
 		cpu_data->depth = trace->depth - 1;
 
-		if (trace->depth < FTRACE_RETFUNC_DEPTH) {
+		if (trace->depth < FTRACE_RETFUNC_DEPTH &&
+		    !WARN_ON_ONCE(trace->depth < 0)) {
 			if (cpu_data->enter_funcs[trace->depth] != trace->func)
 				func_match = 0;
 			cpu_data->enter_funcs[trace->depth] = 0;
diff --git a/kernel/kernel/trace/trace_irqsoff.c b/kernel/kernel/trace/trace_irqsoff.c
index 069942c22..553e71254 100644
--- a/kernel/kernel/trace/trace_irqsoff.c
+++ b/kernel/kernel/trace/trace_irqsoff.c
@@ -110,8 +110,12 @@ static int func_prolog_dec(struct trace_array *tr,
 		return 0;
 
 	local_save_flags(*flags);
-	/* slight chance to get a false positive on tracing_cpu */
-	if (!irqs_disabled_flags(*flags))
+	/*
+	 * Slight chance to get a false positive on tracing_cpu,
+	 * although I'm starting to think there isn't a chance.
+	 * Leave this for now just to be paranoid.
+	 */
+	if (!irqs_disabled_flags(*flags) && !preempt_count())
 		return 0;
 
 	*data = per_cpu_ptr(tr->trace_buffer.data, cpu);
diff --git a/kernel/kernel/trace/trace_printk.c b/kernel/kernel/trace/trace_printk.c
index 060df67db..ad1d6164e 100644
--- a/kernel/kernel/trace/trace_printk.c
+++ b/kernel/kernel/trace/trace_printk.c
@@ -36,6 +36,10 @@ struct trace_bprintk_fmt {
 static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
 {
 	struct trace_bprintk_fmt *pos;
+
+	if (!fmt)
+		return ERR_PTR(-EINVAL);
+
 	list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
 		if (!strcmp(pos->fmt, fmt))
 			return pos;
@@ -57,7 +61,8 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
 	for (iter = start; iter < end; iter++) {
 		struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
 		if (tb_fmt) {
-			*iter = tb_fmt->fmt;
+			if (!IS_ERR(tb_fmt))
+				*iter = tb_fmt->fmt;
 			continue;
 		}
 
@@ -296,6 +301,9 @@ static int t_show(struct seq_file *m, void *v)
 	const char *str = *fmt;
 	int i;
 
+	if (!*fmt)
+		return 0;
+
 	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
 
 	/*