commit 74589f738efd72e07f759a4aabd2e32613aaefb8
Author: Paul Pluzhnikov <ppluzhnikov@google.com>
Date:   Tue Sep 1 08:35:38 2015 -0700

    Filter out NULL entries.

diff --git a/malloc/mtrace.pl b/malloc/mtrace.pl
index adf61c73737160fb..c48e227e9fee8521 100644
--- a/malloc/mtrace.pl
+++ b/malloc/mtrace.pl
@@ -167,7 +167,7 @@ while (<DATA>) {
 		printf ("+ %#0@XXX@x Alloc %d duplicate: %s %s\n",
 			hex($allocaddr), $nr, &location($addrwas{$allocaddr}),
 			$where);
-	    } else {
+	    } elsif ($allocaddr =~ /^0x/) {
 		$allocated{$allocaddr}=$howmuch;
 		$addrwas{$allocaddr}=$where;
 	    }