From bf7c722bd3b30e04a56c2d369fd9f5501a8316d0 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Tue, 12 Feb 2019 16:46:33 +0100
Subject: erts: Fix so that externals with creation 0 compare equal to all

The special creation of 0 is used by internally created externals,
such as when list_to_pid is called. This creation should compare
equal to all externals creations of that external. If it does not
we can end up in very strange scenarios. For instance:

> P = spawn(OtherNode, fun() -> die end).
<8303.60.0>
> link(<8303.60.0>).
true
> flush().
ok

OTP-15613
---
 erts/emulator/beam/erl_monitor_link.c | 3 ++-
 erts/emulator/beam/erl_node_tables.c  | 5 +++--
 erts/emulator/beam/utils.c            | 3 ++-
 3 files changed, 7 insertions(+), 4 deletions(-)

(limited to 'erts/emulator')

diff --git a/erts/emulator/beam/erl_monitor_link.c b/erts/emulator/beam/erl_monitor_link.c
index 3dabd79190..1c6b4afaa3 100644
--- a/erts/emulator/beam/erl_monitor_link.c
+++ b/erts/emulator/beam/erl_monitor_link.c
@@ -191,7 +191,8 @@ ml_cmp_keys(Eterm key1, Eterm key2)
                 if (n1->sysname != n2->sysname)
                     return n1->sysname < n2->sysname ? -1 : 1;
                 ASSERT(n1->creation != n2->creation);
-                return n1->creation < n2->creation ? -1 : 1;
+                if (n1->creation != 0 && n2->creation != 0)
+                    return n1->creation < n2->creation ? -1 : 1;
             }
 
             ndw1 = external_thing_data_words(et1);
diff --git a/erts/emulator/beam/erl_node_tables.c b/erts/emulator/beam/erl_node_tables.c
index 8fe5c3c690..afafaf48dc 100644
--- a/erts/emulator/beam/erl_node_tables.c
+++ b/erts/emulator/beam/erl_node_tables.c
@@ -802,8 +802,9 @@ node_table_hash(void *venp)
 static int
 node_table_cmp(void *venp1, void *venp2)
 {
-    return ((((ErlNode *) venp1)->sysname == ((ErlNode *) venp2)->sysname
-	     && ((ErlNode *) venp1)->creation == ((ErlNode *) venp2)->creation)
+    return ((((ErlNode *) venp1)->sysname == ((ErlNode *) venp2)->sysname) &&
+            ((((ErlNode *) venp1)->creation == ((ErlNode *) venp2)->creation) ||
+             (((ErlNode *) venp1)->creation == 0 || ((ErlNode *) venp2)->creation == 0))
 	    ? 0
 	    : 1);
 }
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index 3fa09e39f2..36a492f00d 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -2701,7 +2701,8 @@ Sint erts_cmp_compound(Eterm a, Eterm b, int exact, int eq_only)
             if((AN)->sysname != (BN)->sysname)				\
                 RETURN_NEQ(erts_cmp_atoms((AN)->sysname, (BN)->sysname));	\
 	    ASSERT((AN)->creation != (BN)->creation);			\
-	    RETURN_NEQ(((AN)->creation < (BN)->creation) ? -1 : 1);	\
+            if ((AN)->creation != 0 && (BN)->creation != 0)             \
+                RETURN_NEQ(((AN)->creation < (BN)->creation) ? -1 : 1);	\
 	}								\
     } while (0)
 
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