diff --git a/ocaml-3.11.0-string-index-from.patch b/ocaml-3.11.0-string-index-from.patch
new file mode 100644
index 0000000..c6a8ddc
--- /dev/null
+++ b/ocaml-3.11.0-string-index-from.patch
@@ -0,0 +1,47 @@
+--- ocaml/stdlib/string.ml	2008/07/22 11:29:00	1.28
++++ ocaml/stdlib/string.ml	2008/11/18 10:29:26	1.29
+@@ -11,7 +11,7 @@
+ (*                                                                     *)
+ (***********************************************************************)
+ 
+-(* $Id: ocaml-3.11.0-string-index-from.patch,v 1.1 2008/11/20 17:52:37 rjones Exp $ *)
++(* $Id: ocaml-3.11.0-string-index-from.patch,v 1.1 2008/11/20 17:52:37 rjones Exp $ *)
+ 
+ (* String operations *)
+ 
+@@ -154,7 +154,7 @@ let index s c = index_rec s (length s) 0
+ 
+ let index_from s i c =
+   let l = length s in
+-  if i < 0 || i >= l then invalid_arg "String.index_from" else
++  if i < 0 || i > l then invalid_arg "String.index_from" else
+   index_rec s l i c;;
+ 
+ let rec rindex_rec s i c =
+@@ -164,22 +164,18 @@ let rec rindex_rec s i c =
+ let rindex s c = rindex_rec s (length s - 1) c;;
+ 
+ let rindex_from s i c =
+-  let l = length s in
+-  if i < 0 || i >= l then invalid_arg "String.rindex_from" else
++  if i < -1 || i >= length s then invalid_arg "String.rindex_from" else
+   rindex_rec s i c;;
+ 
+ let contains_from s i c =
+   let l = length s in
+-  if i < 0 || i >= l then invalid_arg "String.contains_from" else
++  if i < 0 || i > l then invalid_arg "String.contains_from" else
+   try ignore (index_rec s l i c); true with Not_found -> false;;
+ 
+-let contains s c =
+-  let l = length s in
+-  l <> 0 && contains_from s 0 c;;
++let contains s c = contains_from s 0 c;;
+ 
+ let rcontains_from s i c =
+-  let l = length s in
+-  if i < 0 || i >= l then invalid_arg "String.rcontains_from" else
++  if i < 0 || i >= length s then invalid_arg "String.rcontains_from" else
+   try ignore (rindex_rec s i c); true with Not_found -> false;;
+ 
+ type t = string
diff --git a/ocaml.spec b/ocaml.spec
index e0a8f43..c33b9c6 100644
--- a/ocaml.spec
+++ b/ocaml.spec
@@ -2,7 +2,7 @@
 
 Name:           ocaml
 Version:        3.11.0+beta1
-Release:        1%{?dist}
+Release:        2%{?dist}
 
 Summary:        Objective Caml compiler and programming environment
 
@@ -32,6 +32,12 @@ Patch3:         ocaml-3.11.0-ppc64.patch
 # A similar fix went upstream in 3.11.0:
 #Patch5:         ocaml-3.11-dev12-no-executable-stack.patch
 
+# This is a patch from upstream which fixes PR#4637, PR#4582.
+# http://camlcvs.inria.fr/cgi-bin/cvsweb/ocaml/stdlib/string.ml.diff?r1=text&tr1=1.29&r2=text&tr2=1.28
+# commonly manifested as errors thrown saying:
+# Invalid_argument("String.index_from")
+Patch6:          ocaml-3.11.0-string-index-from.patch
+
 BuildRoot:      %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
 
 BuildRequires:  ncurses-devel
@@ -206,6 +212,7 @@ man pages and info files.
 %patch3 -p1 -b .ppc64
 #%patch4 -p1 -b .map32bit
 #%patch5 -p0 -b .noexecstack
+%patch6 -p1 -b .stringindexfrom
 
 cp %{SOURCE2} refman.pdf
 
@@ -446,6 +453,9 @@ fi
 
 
 %changelog
+* Thu Nov 20 2008 Richard W.M. Jones <rjones@redhat.com> - 3.11.0+beta1-2
+- Fix Invalid_argument("String.index_from") with patch from upstream.
+
 * Tue Nov 18 2008 Richard W.M. Jones <rjones@redhat.com> - 3.11.0+beta1-1
 - Rebuild for major new upstream release of 3.11.0 for Fedora 11.