1 files changed, 11 insertions, 21 deletions

diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h
index 42ed14e69c..a14f4f51d8 100644
--- a/erts/emulator/beam/erl_message.h
+++ b/erts/emulator/beam/erl_message.h
@@ -167,14 +167,12 @@ typedef struct {
     Sint len;            /* queue length */
 
     /*
-     * The following two fields are used by the recv_mark/1 and
+     * The following field is used by the recv_mark/1 and
      * recv_set/1 instructions.
      */
-    BeamInstr* mark;		/* address to rec_loop/2 instruction */
     ErtsMessage** saved_last;	/* saved last pointer */
 } ErlMessageQueue;
 
-#ifdef ERTS_SMP
 
 typedef struct {
     ErtsMessage* first;
@@ -190,7 +188,6 @@ typedef struct erl_trace_message_queue__ {
     Sint len;            /* queue length */
 } ErlTraceMessageQueue;
 
-#endif
 
 /* Get "current" message */
 #define PEEK_MESSAGE(p)  (*(p)->msg.save)
@@ -207,7 +204,6 @@ typedef struct erl_trace_message_queue__ {
         (p)->where.len += (num_msgs);                                   \
     } while(0)
 
-#ifdef ERTS_SMP
 
 /* Add message last in private message queue */
 #define LINK_MESSAGE_PRIVQ(p, first_msg, last_msg, len)                 \
@@ -219,7 +215,7 @@ typedef struct erl_trace_message_queue__ {
 #define LINK_MESSAGE(p, first_msg, last_msg, len)       \
     LINK_MESSAGE_IMPL(p, first_msg, last_msg, len, msg_inq)
 
-#define ERTS_SMP_MSGQ_MV_INQ2PRIVQ(p)                   \
+#define ERTS_MSGQ_MV_INQ2PRIVQ(p)                   \
     do {                                                \
         if (p->msg_inq.first) {                         \
             *p->msg.last = p->msg_inq.first;            \
@@ -231,17 +227,6 @@ typedef struct erl_trace_message_queue__ {
         }                                               \
     } while (0)
 
-#else
-
-#define ERTS_SMP_MSGQ_MV_INQ2PRIVQ(p)
-
-/* Add message last_msg in message queue */
-#define LINK_MESSAGE(p, first_msg, last_msg, len)                       \
-    do {                                                                \
-        LINK_MESSAGE_IMPL(p, first_msg, last_msg, len, msg);            \
-    } while(0)
-
-#endif
 
 /* Unlink current message */
 #define UNLINK_MESSAGE(p,msgp) do { \
@@ -250,12 +235,17 @@ typedef struct erl_trace_message_queue__ {
      (p)->msg.len--; \
      if (__mp == NULL) \
          (p)->msg.last = (p)->msg.save; \
-     (p)->msg.mark = 0; \
 } while(0)
 
-/* Reset message save point (after receive match) */
-#define JOIN_MESSAGE(p) \
-     (p)->msg.save = &(p)->msg.first
+/*
+ * Reset message save point (after receive match).
+ * Also invalidate the saved position since it may no
+ * longer be safe to use.
+ */
+#define JOIN_MESSAGE(p) do {                    \
+    (p)->msg.save = &(p)->msg.first;            \
+    (p)->msg.saved_last = 0;                    \
+} while(0)
 
 /* Save current message */
 #define SAVE_MESSAGE(p) \