From d7e1e4046b97df4b73591a8e9e2dc06c5daad863 Mon Sep 17 00:00:00 2001
From: Jeremy Lakeman <jeremy.lakeman@flinders.edu.au>
Date: Mon, 2 May 2016 10:48:36 +0930
Subject: [PATCH] Add debug messages to diagnose possible ref counting bug

---
 conf_schema.h       |  1 +
 overlay_interface.h | 17 ++++++++++++-----
 route_link.c        | 20 ++++++++++++--------
 3 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/conf_schema.h b/conf_schema.h
index 8cc2fac0..c5ac1399 100644
--- a/conf_schema.h
+++ b/conf_schema.h
@@ -268,6 +268,7 @@ ATOM(bool_t, vomp,                      0, boolean,, "")
 ATOM(bool_t, profiling,                 0, boolean,, "")
 ATOM(bool_t, linkstate,                 0, boolean,, "")
 ATOM(bool_t, watchdog,                  0, boolean,, "")
+ATOM(bool_t, ref_counts,                0, boolean,, "")
 END_STRUCT
 
 #define LOG_FORMAT_OPTIONS \
diff --git a/overlay_interface.h b/overlay_interface.h
index d78a7567..31d02349 100644
--- a/overlay_interface.h
+++ b/overlay_interface.h
@@ -101,11 +101,18 @@ typedef struct overlay_interface {
  */
 extern overlay_interface overlay_interfaces[OVERLAY_MAX_INTERFACES];
 
-struct network_destination * new_destination(struct overlay_interface *interface);
-struct network_destination * create_unicast_destination(struct socket_address *addr, struct overlay_interface *interface);
-struct network_destination * add_destination_ref(struct network_destination *ref);
-void release_destination_ref(struct network_destination *ref);
-int set_destination_ref(struct network_destination **ptr, struct network_destination *ref);
+struct network_destination * _new_destination(struct __sourceloc __whence, struct overlay_interface *interface);
+struct network_destination * _create_unicast_destination(struct __sourceloc __whence, struct socket_address *addr, struct overlay_interface *interface);
+struct network_destination * _add_destination_ref(struct __sourceloc __whence, struct network_destination *ref);
+void _release_destination_ref(struct __sourceloc __whence, struct network_destination *ref);
+int _set_destination_ref(struct __sourceloc __whence, struct network_destination **ptr, struct network_destination *ref);
+
+#define new_destination(I) _new_destination(__WHENCE__, I)
+#define create_unicast_destination(A, I) _create_unicast_destination(__WHENCE__, A, I)
+#define add_destination_ref(R) _add_destination_ref(__WHENCE__, R)
+#define release_destination_ref(R) _release_destination_ref(__WHENCE__, R)
+#define set_destination_ref(P, R) _set_destination_ref(__WHENCE__, P, R)
+
 void overlay_interface_config_change();
 
 struct config_mdp_iftype;
diff --git a/route_link.c b/route_link.c
index 4bfdadc7..e7d1c22b 100644
--- a/route_link.c
+++ b/route_link.c
@@ -174,7 +174,7 @@ struct neighbour *neighbours=NULL;
 unsigned neighbour_count=0;
 int route_version=0;
 
-struct network_destination * new_destination(struct overlay_interface *interface){
+struct network_destination * _new_destination(struct __sourceloc __whence, struct overlay_interface *interface){
   assert(interface);
   struct network_destination *ret = emalloc_zero(sizeof(struct network_destination));
   if (ret){
@@ -184,11 +184,12 @@ struct network_destination * new_destination(struct overlay_interface *interface
     ret->last_tx = TIME_MS_NEVER_HAS;
     ret->sequence_number = -1;
     ret->last_ack_seq = -1;
+    DEBUGF(ref_counts, "Created destination %p refs %u", ret, ret->_ref_count);
   }
   return ret;
 }
 
-struct network_destination * create_unicast_destination(struct socket_address *addr, struct overlay_interface *interface){
+struct network_destination * _create_unicast_destination(struct __sourceloc whence, struct socket_address *addr, struct overlay_interface *interface){
   if (!interface && addr->addr.sa_family == AF_INET)
     interface = overlay_interface_find(addr->inet.sin_addr, 1);
   if (!interface){
@@ -203,7 +204,7 @@ struct network_destination * create_unicast_destination(struct socket_address *a
     return NULL;
   if (!interface->ifconfig.unicast.send)
     return NULL;
-  struct network_destination *ret = new_destination(interface);
+  struct network_destination *ret = _new_destination(whence, interface);
   if (ret){
     ret->address = *addr;
     ret->unicast = 1;
@@ -212,26 +213,29 @@ struct network_destination * create_unicast_destination(struct socket_address *a
   return ret;
 }
 
-struct network_destination * add_destination_ref(struct network_destination *ref){
+struct network_destination * _add_destination_ref(struct __sourceloc __whence, struct network_destination *ref){
   ref->_ref_count++;
+  DEBUGF(ref_counts, "Added destination %p refs %u", ref, ref->_ref_count);
   return ref;
 }
 
-void release_destination_ref(struct network_destination *ref){
+void _release_destination_ref(struct __sourceloc __whence, struct network_destination *ref){
   if (ref->_ref_count<=1){
+    DEBUGF(ref_counts, "Released destination %p refs %u", ref, ref->_ref_count);
     free(ref);
   }else{
     ref->_ref_count--;
+    DEBUGF(ref_counts, "Decremented destination %p refs %u", ref, ref->_ref_count);
   }
 }
 
-int set_destination_ref(struct network_destination **ptr, struct network_destination *ref){
+int _set_destination_ref(struct __sourceloc __whence, struct network_destination **ptr, struct network_destination *ref){
   if (ref==*ptr)
     return 0;
   if (ref)
-    add_destination_ref(ref);
+    _add_destination_ref(__whence, ref);
   if (*ptr)
-    release_destination_ref(*ptr);
+    _release_destination_ref(__whence, *ptr);
   *ptr = ref;
   return 1;
 }