diff --git a/sys/compat/linux/linux_futex.c b/sys/compat/linux/linux_futex.c
index be052069f1d..f4423b4546f 100644
--- a/sys/compat/linux/linux_futex.c
+++ b/sys/compat/linux/linux_futex.c
@@ -118,6 +118,15 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		    args->val, args->uaddr2, args->val3);
 #endif
 
+	/* 
+	 * Our implementation provides only privates futexes. Most of the apps
+	 * should use private futexes but don't claim so. Therefore we treat
+	 * all futexes as private by clearing the FUTEX_PRIVATE_FLAG. It works
+	 * in most cases (ie. when futexes are not shared on file descriptor
+	 * or between different processes.).
+	 */
+	args->op = (args->op & ~LINUX_FUTEX_PRIVATE_FLAG);
+
 	switch (args->op) {
 	case LINUX_FUTEX_WAIT:
 		FUTEX_SYSTEM_LOCK;
@@ -264,10 +273,11 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		break;
 
 	case LINUX_FUTEX_FD:
-		/* XXX: Linux plans to remove this operation */
+#ifdef DEBUG
 		printf("linux_sys_futex: unimplemented op %d\n",
 		    args->op);
-		break;
+#endif
+		return (ENOSYS);
 
 	case LINUX_FUTEX_WAKE_OP:
 		FUTEX_SYSTEM_LOCK;
@@ -324,6 +334,18 @@ linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
 		FUTEX_SYSTEM_UNLOCK;
 		break;
 
+	case LINUX_FUTEX_LOCK_PI:
+		/* not yet implemented */
+		return (ENOSYS);
+
+	case LINUX_FUTEX_UNLOCK_PI:
+		/* not yet implemented */
+		return (ENOSYS);
+
+	case LINUX_FUTEX_TRYLOCK_PI:
+		/* not yet implemented */
+		return (ENOSYS);
+
 	default:
 		printf("linux_sys_futex: unknown op %d\n",
 		    args->op);
diff --git a/sys/compat/linux/linux_futex.h b/sys/compat/linux/linux_futex.h
index 1ba1ce2d516..3ca6f3bfff9 100644
--- a/sys/compat/linux/linux_futex.h
+++ b/sys/compat/linux/linux_futex.h
@@ -42,6 +42,11 @@
 #define LINUX_FUTEX_REQUEUE	3
 #define LINUX_FUTEX_CMP_REQUEUE	4
 #define LINUX_FUTEX_WAKE_OP	5
+#define LINUX_FUTEX_LOCK_PI	6
+#define LINUX_FUTEX_UNLOCK_PI	7
+#define LINUX_FUTEX_TRYLOCK_PI	8
+
+#define LINUX_FUTEX_PRIVATE_FLAG	128
 
 #define FUTEX_OP_SET            0	/* *(int *)UADDR2 = OPARG; */
 #define FUTEX_OP_ADD            1	/* *(int *)UADDR2 += OPARG; */