diff -r c38988024f1f src/kern/linux/linux.hh
--- a/src/kern/linux/linux.hh	Wed Sep 19 06:15:46 2012 -0400
+++ b/src/kern/linux/linux.hh	Thu Sep 20 17:47:14 2012 +0200
@@ -225,6 +225,7 @@
     static const unsigned TGT_FUTEX_WAKE  = 1;
     static const unsigned TGT_EAGAIN      = 11;
     static const unsigned TGT_EWOULDBLOCK = TGT_EAGAIN;
+    static const unsigned TGT_FUTEX_PRIVATE_FLAG = 128;
 
 };  // class Linux
 
diff -r c38988024f1f src/sim/syscall_emul.hh
--- a/src/sim/syscall_emul.hh	Wed Sep 19 06:15:46 2012 -0400
+++ b/src/sim/syscall_emul.hh	Thu Sep 20 17:47:14 2012 +0200
@@ -359,6 +359,7 @@
     DPRINTF(SyscallVerbose, "In sys_futex: Address=%llx, op=%d, val=%d\n",
             uaddr, op, val);
 
+    op &= ~OS::TGT_FUTEX_PRIVATE_FLAG;
 
     if (op == OS::TGT_FUTEX_WAIT) {
         if (timeout != 0) {
@@ -410,7 +411,7 @@
                                 "thread contexts\n", wokenUp);
         return wokenUp;
     } else {
-        warn("sys_futex: op %d is not implemented, just returning...");
+        warn("sys_futex: op %d is not implemented, just returning...", op);
         return 0;
     }