diff -urNp coreutils-8.17-orig/src/extent-scan.c coreutils-8.17/src/extent-scan.c

--- coreutils-8.17-orig/src/extent-scan.c	2012-05-02 10:31:47.000000000 +0200

+++ coreutils-8.17/src/extent-scan.c	2012-11-05 12:05:36.732370966 +0100

@@ -89,7 +89,7 @@ extern bool

 extent_scan_read (struct extent_scan *scan)

 {

   unsigned int si = 0;

-  struct extent_info *last_ei IF_LINT ( = scan->ext_info);

+  struct extent_info *last_ei = scan->ext_info;

   while (true)

     {

@@ -127,8 +127,14 @@ extent_scan_read (struct extent_scan *sc

       assert (scan->ei_count <= SIZE_MAX - fiemap->fm_mapped_extents);

       scan->ei_count += fiemap->fm_mapped_extents;

-      scan->ext_info = xnrealloc (scan->ext_info, scan->ei_count,

-                                  sizeof (struct extent_info));

+      {

+        /* last_ei points into a buffer that may be freed via xnrealloc.

+           Record its offset and adjust after allocation. */

+        size_t prev_idx = last_ei - scan->ext_info;

+        scan->ext_info = xnrealloc (scan->ext_info, scan->ei_count,

+        sizeof (struct extent_info));

+        last_ei = scan->ext_info + prev_idx;

+      }

       unsigned int i = 0;

       for (i = 0; i < fiemap->fm_mapped_extents; i++)