diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index 0ae20b83eec8..46fb9612d884 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -29,25 +29,26 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
 		unsigned long sym_flags);
 extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
 				 size_t cnt);
-int trace_seq_puts(struct trace_seq *s, const char *str);
-int trace_seq_putc(struct trace_seq *s, unsigned char c);
-int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len);
-int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len);
-void *trace_seq_reserve(struct trace_seq *s, size_t len);
-int trace_seq_path(struct trace_seq *s, struct path *path);
-int seq_print_userip_objs(const struct userstack_entry *entry,
-			  struct trace_seq *s, unsigned long sym_flags);
-int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
-		      unsigned long ip, unsigned long sym_flags);
+extern int trace_seq_puts(struct trace_seq *s, const char *str);
+extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
+extern int trace_seq_putmem(struct trace_seq *s, void *mem, size_t len);
+extern int trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len);
+extern void *trace_seq_reserve(struct trace_seq *s, size_t len);
+extern int trace_seq_path(struct trace_seq *s, struct path *path);
+extern int seq_print_userip_objs(const struct userstack_entry *entry,
+				 struct trace_seq *s, unsigned long sym_flags);
+extern int seq_print_user_ip(struct trace_seq *s, struct mm_struct *mm,
+			     unsigned long ip, unsigned long sym_flags);
 
-int trace_print_context(struct trace_iterator *iter);
-int trace_print_lat_context(struct trace_iterator *iter);
+extern int trace_print_context(struct trace_iterator *iter);
+extern int trace_print_lat_context(struct trace_iterator *iter);
 
-struct trace_event *ftrace_find_event(int type);
-int register_ftrace_event(struct trace_event *event);
-int unregister_ftrace_event(struct trace_event *event);
+extern struct trace_event *ftrace_find_event(int type);
+extern int register_ftrace_event(struct trace_event *event);
+extern int unregister_ftrace_event(struct trace_event *event);
 
-enum print_line_t trace_nop_print(struct trace_iterator *iter, int flags);
+extern enum print_line_t trace_nop_print(struct trace_iterator *iter,
+					 int flags);
 
 #define MAX_MEMHEX_BYTES	8
 #define HEX_CHARS		(MAX_MEMHEX_BYTES*2 + 1)