ring-buffer: Add recording of ring buffer recursion into recursed_functions

Add a new config RING_BUFFER_RECORD_RECURSION that will place functions that
recurse from the ring buffer into the ftrace recused_functions file.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index dc83b3fa9fe7..ab68f28b8f4b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4,6 +4,7 @@
  *
  * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
  */
+#include <linux/trace_recursion.h>
 #include <linux/trace_events.h>
 #include <linux/ring_buffer.h>
 #include <linux/trace_clock.h>
@@ -3006,6 +3007,13 @@ rb_wakeups(struct trace_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 	irq_work_queue(&cpu_buffer->irq_work.work);
 }
 
+#ifdef CONFIG_RING_BUFFER_RECORD_RECURSION
+# define do_ring_buffer_record_recursion()	\
+	do_ftrace_record_recursion(_THIS_IP_, _RET_IP_)
+#else
+# define do_ring_buffer_record_recursion() do { } while (0)
+#endif
+
 /*
  * The lock and unlock are done within a preempt disable section.
  * The current_context per_cpu variable can only be modified
@@ -3088,8 +3096,10 @@ trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer)
 		 * been updated yet. In this case, use the TRANSITION bit.
 		 */
 		bit = RB_CTX_TRANSITION;
-		if (val & (1 << (bit + cpu_buffer->nest)))
+		if (val & (1 << (bit + cpu_buffer->nest))) {
+			do_ring_buffer_record_recursion();
 			return 1;
+		}
 	}
 
 	val |= (1 << (bit + cpu_buffer->nest));