diff --git a/mercurial/revlogutils/nodemap.py b/mercurial/revlogutils/nodemap.py
--- a/mercurial/revlogutils/nodemap.py
+++ b/mercurial/revlogutils/nodemap.py
@@ -53,7 +53,11 @@
     try:
         with revlog.opener(filename) as fd:
             if use_mmap:
-                data = util.buffer(util.mmapread(fd, data_length))
+                try:
+                    data = util.buffer(util.mmapread(fd, data_length))
+                except ValueError:
+                    # raised when the read file is too small
+                    data = b''
             else:
                 data = fd.read(data_length)
     except (IOError, OSError) as e:
diff --git a/tests/test-persistent-nodemap.t b/tests/test-persistent-nodemap.t
--- a/tests/test-persistent-nodemap.t
+++ b/tests/test-persistent-nodemap.t
@@ -795,7 +795,11 @@
 
 Check that Mercurial reaction to this event
 
-  $ hg -R corruption-test-repo log -r .
-  abort: index 00changelog.i is corrupted
-  [50]
+  $ hg -R corruption-test-repo log -r . --traceback
+  changeset:   5005:90d5d3ba2fc4
+  tag:         tip
+  user:        test
+  date:        Thu Jan 01 00:00:00 1970 +0000
+  summary:     a2
+