Merge tag 'trace-v4.18-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes and cleanups from Steven Rostedt:
 "While cleaning out my INBOX, I found a few patches that were lost in
  the noise. These are minor bug fixes and clean ups. Those include:

   - avoid a string overflow

   - code that didn't match the comment (but should)

   - a small code optimization (use of a conditional)

   - quiet printf warnings

   - nuke unused code

   - fix function graph interrupt annotation"

* tag 'trace-v4.18-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix missing return symbol in function_graph output
  ftrace: Nuke clear_ftrace_function
  tracing: Use __printf markup to silence compiler
  tracing: Optimize trace_buffer_iter() logic
  tracing: Make create_filter() code match the comments
  tracing: Avoid string overflow

include/linux/ftrace.h

@@ -223,7 +223,6 @@ extern enum ftrace_tracing_type_t ftrace_tracing_type;
  */
 int register_ftrace_function(struct ftrace_ops *ops);
 int unregister_ftrace_function(struct ftrace_ops *ops);
-void clear_ftrace_function(void);
 
 extern void ftrace_stub(unsigned long a0, unsigned long a1,
 			struct ftrace_ops *op, struct pt_regs *regs);
@@ -239,7 +238,6 @@ static inline int ftrace_nr_registered_ops(void)
 {
 	return 0;
 }
-static inline void clear_ftrace_function(void) { }
 static inline void ftrace_kill(void) { }
 static inline void ftrace_free_init_mem(void) { }
 static inline void ftrace_free_mem(struct module *mod, void *start, void *end) { }

kernel/trace/ftrace.c

@@ -192,17 +192,6 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 	op->saved_func(ip, parent_ip, op, regs);
 }
 
-/**
- * clear_ftrace_function - reset the ftrace function
- *
- * This NULLs the ftrace function and in essence stops
- * tracing.  There may be lag
- */
-void clear_ftrace_function(void)
-{
-	ftrace_trace_function = ftrace_stub;
-}
-
 static void ftrace_sync(struct work_struct *work)
 {
 	/*
@@ -6689,7 +6678,7 @@ void ftrace_kill(void)
 {
 	ftrace_disabled = 1;
 	ftrace_enabled = 0;
-	clear_ftrace_function();
+	ftrace_trace_function = ftrace_stub;
 }
 
 /**

kernel/trace/trace.c

@@ -2953,6 +2953,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 
+__printf(3, 0)
 static int
 __trace_array_vprintk(struct ring_buffer *buffer,
 		      unsigned long ip, const char *fmt, va_list args)
@@ -3007,12 +3008,14 @@ __trace_array_vprintk(struct ring_buffer *buffer,
 	return len;
 }
 
+__printf(3, 0)
 int trace_array_vprintk(struct trace_array *tr,
 			unsigned long ip, const char *fmt, va_list args)
 {
 	return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
 }
 
+__printf(3, 0)
 int trace_array_printk(struct trace_array *tr,
 		       unsigned long ip, const char *fmt, ...)
 {
@@ -3028,6 +3031,7 @@ int trace_array_printk(struct trace_array *tr,
 	return ret;
 }
 
+__printf(3, 4)
 int trace_array_printk_buf(struct ring_buffer *buffer,
 			   unsigned long ip, const char *fmt, ...)
 {
@@ -3043,6 +3047,7 @@ int trace_array_printk_buf(struct ring_buffer *buffer,
 	return ret;
 }
 
+__printf(2, 0)
 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 {
 	return trace_array_vprintk(&global_trace, ip, fmt, args);

kernel/trace/trace.h

@@ -583,9 +583,7 @@ static __always_inline void trace_clear_recursion(int bit)
 static inline struct ring_buffer_iter *
 trace_buffer_iter(struct trace_iterator *iter, int cpu)
 {
-	if (iter->buffer_iter && iter->buffer_iter[cpu])
-		return iter->buffer_iter[cpu];
-	return NULL;
+	return iter->buffer_iter ? iter->buffer_iter[cpu] : NULL;
 }
 
 int tracer_init(struct tracer *t, struct trace_array *tr);

kernel/trace/trace_events_filter.c

@@ -1701,6 +1701,7 @@ static void create_filter_finish(struct filter_parse_error *pe)
  * @filter_str: filter string
  * @set_str: remember @filter_str and enable detailed error in filter
  * @filterp: out param for created filter (always updated on return)
+ *           Must be a pointer that references a NULL pointer.
  *
  * Creates a filter for @call with @filter_str.  If @set_str is %true,
  * @filter_str is copied and recorded in the new filter.
@@ -1718,6 +1719,10 @@ static int create_filter(struct trace_event_call *call,
 	struct filter_parse_error *pe = NULL;
 	int err;
 
+	/* filterp must point to NULL */
+	if (WARN_ON(*filterp))
+		*filterp = NULL;
+
 	err = create_filter_start(filter_string, set_str, &pe, filterp);
 	if (err)
 		return err;

kernel/trace/trace_events_hist.c

@@ -393,7 +393,7 @@ static void hist_err_event(char *str, char *system, char *event, char *var)
 	else if (system)
 		snprintf(err, MAX_FILTER_STR_VAL, "%s.%s", system, event);
 	else
-		strncpy(err, var, MAX_FILTER_STR_VAL);
+		strscpy(err, var, MAX_FILTER_STR_VAL);
 
 	hist_err(str, err);
 }

kernel/trace/trace_functions_graph.c

@@ -831,6 +831,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 	struct ftrace_graph_ret *graph_ret;
 	struct ftrace_graph_ent *call;
 	unsigned long long duration;
+	int cpu = iter->cpu;
 	int i;
 
 	graph_ret = &ret_entry->ret;
@@ -839,7 +840,6 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 
 	if (data) {
 		struct fgraph_cpu_data *cpu_data;
-		int cpu = iter->cpu;
 
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 
@@ -869,6 +869,9 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 
 	trace_seq_printf(s, "%ps();\n", (void *)call->func);
 
+	print_graph_irq(iter, graph_ret->func, TRACE_GRAPH_RET,
+			cpu, iter->ent->pid, flags);
+
 	return trace_handle_return(s);
 }