1 files changed, 9 insertions, 0 deletions
diff --git a/src/insdel.c b/src/insdel.c
index 08f04d3ddca..a6f006a521d 100644
--- a/src/insdel.c
+++ b/src/insdel.c
@@ -29,6 +29,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include "buffer.h"
 #include "window.h"
 #include "region-cache.h"
+#include "pdumper.h"
 
 static void insert_from_string_1 (Lisp_Object, ptrdiff_t, ptrdiff_t, ptrdiff_t,
 				  ptrdiff_t, bool, bool);
@@ -1927,6 +1928,14 @@ prepare_to_modify_buffer_1 (ptrdiff_t start, ptrdiff_t end,
   if (!NILP (BVAR (current_buffer, read_only)))
     Fbarf_if_buffer_read_only (temp);
 
+  /* If we're about to modify a buffer the contents of which come from
+     a dump file, copy the contents to private storage first so we
+     don't take a COW fault on the buffer text and keep it around
+     forever.  */
+  if (pdumper_object_p (BEG_ADDR))
+    enlarge_buffer_text (current_buffer, 0);
+  eassert (!pdumper_object_p (BEG_ADDR));
+
   run_undoable_change();
 
   bset_redisplay (current_buffer);