diff --git a/coregrind/vg_syscalls.c b/coregrind/vg_syscalls.c
index e4eeb2a..0e5ffb0 100644
--- a/coregrind/vg_syscalls.c
+++ b/coregrind/vg_syscalls.c
@@ -311,6 +311,9 @@
 {
    OpenFd *i = allocated_fds;
 
+   if (fd > VG_MAX_FD)
+      return;			/* Valgrind internal */
+
    while(i) {
       if(i->fd == fd) {
          if(i->prev)