--- a/mercurial/graphmod.py	Tue Mar 21 18:36:14 2017 -0400
+++ b/mercurial/graphmod.py	Mon Mar 20 11:50:55 2017 +0900
@@ -182,6 +182,9 @@
     knownparents = []
     newparents = []
     for ptype, parent in parents:
+        if parent == rev:
+            # self reference (should only be seen in null rev)
+            continue
         if parent in seen:
             knownparents.append(parent)
         else:
@@ -191,8 +194,7 @@
     ncols = len(seen)
     nextseen = seen[:]
     nextseen[nodeidx:nodeidx + 1] = newparents
-    edges = [(nodeidx, nextseen.index(p))
-             for p in knownparents if p != nullrev]
+    edges = [(nodeidx, nextseen.index(p)) for p in knownparents]
 
     seen[:] = nextseen
     while len(newparents) > 2:

--- a/tests/test-glog.t	Tue Mar 21 18:36:14 2017 -0400
+++ b/tests/test-glog.t	Mon Mar 20 11:50:55 2017 +0900
@@ -3424,3 +3424,39 @@
      summary:     0
   
 
+  $ cd ..
+
+Multiple roots (issue5440):
+
+  $ hg init multiroots
+  $ cd multiroots
+  $ cat <<EOF > .hg/hgrc
+  > [ui]
+  > logtemplate = '{rev} {desc}\n\n'
+  > EOF
+
+  $ touch foo
+  $ hg ci -Aqm foo
+  $ hg co -q null
+  $ touch bar
+  $ hg ci -Aqm bar
+
+  $ hg log -Gr null:
+  @  1 bar
+  |
+  | o  0 foo
+  |/
+  o  -1
+  
+  $ hg log -Gr null+0
+  o  0 foo
+  |
+  o  -1
+  
+  $ hg log -Gr null+1
+  @  1 bar
+  |
+  o  -1
+  
+
+  $ cd ..