diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f35ba1b210..67049161c2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2014-08-19  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	Fix -fsanitize=address on unreadable inferior strings.
+	* valprint.c (val_print_string): Fix access before BUFFER.
+
 2014-08-19  Simon Marchi  <simon.marchi@ericsson.com>
 
 	* target.c (target_struct_size): Remove.
diff --git a/gdb/valprint.c b/gdb/valprint.c
index d3ab2675fc..a87d67cc78 100644
--- a/gdb/valprint.c
+++ b/gdb/valprint.c
@@ -2510,8 +2510,10 @@ val_print_string (struct type *elttype, const char *encoding,
      LEN is -1.  */
 
   /* Determine found_nul by looking at the last character read.  */
-  found_nul = extract_unsigned_integer (buffer + bytes_read - width, width,
-					byte_order) == 0;
+  found_nul = 0;
+  if (bytes_read >= width)
+    found_nul = extract_unsigned_integer (buffer + bytes_read - width, width,
+					  byte_order) == 0;
   if (len == -1 && !found_nul)
     {
       gdb_byte *peekbuf;