erts: Fix bug when scheduling monitor-msg combo

Bug introduced in master by
613cde66c25464121f2f6dace99782bad0e07d9b

3 files changed, 27 insertions, 10 deletions

diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index bea7a0fe86..507cc989d2 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -379,7 +379,10 @@ queue_messages(Process* receiver,
 	erts_proc_unlock(receiver, ERTS_PROC_LOCK_MSGQ);
     }
 
-    erts_proc_notify_new_message(receiver, receiver_locks);
+    if (last == &first->next)
+        erts_proc_notify_new_message(receiver, receiver_locks);
+    else
+        erts_proc_notify_new_sig(receiver, state, ERTS_PSFLG_ACTIVE);
 }
 
 static ERTS_INLINE
diff --git a/erts/emulator/beam/erl_proc_sig_queue.c b/erts/emulator/beam/erl_proc_sig_queue.c
index 17fdc98183..6d81044c39 100644
--- a/erts/emulator/beam/erl_proc_sig_queue.c
+++ b/erts/emulator/beam/erl_proc_sig_queue.c
@@ -680,15 +680,7 @@ first_last_done:
         sig_enqueue_trace_cleanup(first, sig, last);
     }
 
-    if (!(state & (ERTS_PSFLG_EXITING
-                   | ERTS_PSFLG_ACTIVE_SYS
-                   | ERTS_PSFLG_SIG_IN_Q))) {
-        /* Schedule process... */
-        state = erts_proc_sys_schedule(rp, state, 0);
-    }
-
-    if (state & (ERTS_PSFLG_DIRTY_RUNNING | ERTS_PSFLG_DIRTY_RUNNING_SYS))
-        erts_make_dirty_proc_handled(rp->common.id, state, -1);
+    erts_proc_notify_new_sig(rp, state, 0);
 
     if (!is_normal_sched)
         erts_proc_dec_refc(rp);
diff --git a/erts/emulator/beam/erl_proc_sig_queue.h b/erts/emulator/beam/erl_proc_sig_queue.h
index 3ea6418283..8edd277309 100644
--- a/erts/emulator/beam/erl_proc_sig_queue.h
+++ b/erts/emulator/beam/erl_proc_sig_queue.h
@@ -744,6 +744,10 @@ erts_enqueue_signals(Process *rp, ErtsMessage *first,
 void
 erts_proc_sig_send_pending(ErtsSchedulerData* esdp);
 
+/* SVERK Doc me up! */
+ERTS_GLB_INLINE void erts_proc_notify_new_sig(Process* rp, erts_aint32_t state,
+                                              erts_aint32_t enable_flag);
+
 void erts_make_dirty_proc_handled(Eterm pid, erts_aint32_t state,
                                   erts_aint32_t prio);
 
@@ -882,6 +886,24 @@ erts_proc_sig_fetch(Process *proc)
     return res;
 }
 
+ERTS_GLB_INLINE void
+erts_proc_notify_new_sig(Process* rp, erts_aint32_t state,
+                         erts_aint32_t enable_flag)
+{
+    if (~(state & (ERTS_PSFLG_EXITING
+                   | ERTS_PSFLG_ACTIVE_SYS
+                   | ERTS_PSFLG_SIG_IN_Q))
+        | (~state & enable_flag)) {
+        /* Schedule process... */
+        state = erts_proc_sys_schedule(rp, state, enable_flag);
+    }
+
+    if (state & (ERTS_PSFLG_DIRTY_RUNNING
+                 | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
+        erts_make_dirty_proc_handled(rp->common.id, state, -1);
+    }
+}
+
 #endif /* ERTS_GLB_INLINE_INCL_FUNC_DEF */
 
 #endif /* ERTS_PROC_SIG_QUEUE_H__ */