diff --git a/coregrind/vg_main.c b/coregrind/vg_main.c
index f007714..2dcfb7a 100644
--- a/coregrind/vg_main.c
+++ b/coregrind/vg_main.c
@@ -154,7 +154,7 @@
 Int VG_(main_pgrp);
 
 /* Maximum allowed application-visible file descriptor */
-Int VG_(max_fd);
+Int VG_(max_fd) = -1;
 
 /* Words. */
 static Int baB_off = 0;
@@ -1403,11 +1403,6 @@
 
    vg_assert(VG_(clstk_end) == VG_(client_end));
 
-   if (kp->vgexecfd != -1)
-      VG_(vgexecfd) = VG_(safe_fd)(kp->vgexecfd);
-   if (kp->clexecfd != -1)
-      VG_(clexecfd) = VG_(safe_fd)(kp->clexecfd);
-
    if (0) {
       if (VG_(have_ssestate))
          VG_(printf)("Looks like a SSE-capable CPU\n");
@@ -1437,6 +1432,11 @@
    /* Update the soft limit. */
    VG_(setrlimit)(VKI_RLIMIT_NOFILE, &rl);
 
+   if (kp->vgexecfd != -1)
+      VG_(vgexecfd) = VG_(safe_fd)(kp->vgexecfd);
+   if (kp->clexecfd != -1)
+      VG_(clexecfd) = VG_(safe_fd)(kp->clexecfd);
+
    /* Read /proc/self/maps into a buffer.  Must be before:
       - SK_(pre_clo_init)(): so that if it calls VG_(malloc)(), any mmap'd
         superblocks are not erroneously identified as being owned by the
diff --git a/coregrind/vg_mylibc.c b/coregrind/vg_mylibc.c
index 850e178..c061535 100644
--- a/coregrind/vg_mylibc.c
+++ b/coregrind/vg_mylibc.c
@@ -1203,6 +1203,8 @@
 {
    Int newfd;
 
+   vg_assert(VG_(max_fd) != -1);
+
    newfd = VG_(fcntl)(oldfd, VKI_F_DUPFD, VG_(max_fd)+1);
    if (newfd != -1)
       VG_(close)(oldfd);