diff --git i/src/.gdbinit w/src/.gdbinit
index a4e9f70..d17d1ba 100644
--- i/src/.gdbinit
+++ w/src/.gdbinit
@@ -1280,3 +1280,22 @@ commands
   end
   continue
 end
+
+# bug 24315
+break re_match_2_internal if (size2>2000 && size2==stop)
+commands
+  p debug = 1
+  continue
+end
+break debug_spot
+commands
+  watch -l string1[0]
+  disable 4
+  # cond 4 (string1[0] != 'D')
+  # continue
+end
+# break debug_malloc if ((mem <= 0x1834980) && (0x1834980 < mem + size))
+
+
+
+
diff --git i/src/gmalloc.c w/src/gmalloc.c
index 00b8364..5084609 100644
--- i/src/gmalloc.c
+++ w/src/gmalloc.c
@@ -914,6 +914,10 @@ _malloc_internal_nolock (size_t size)
   return result;
 }
 
+void debug_malloc (void* mem, size_t size)
+{
+}
+
 void *
 _malloc_internal (size_t size)
 {
@@ -923,6 +927,7 @@ _malloc_internal (size_t size)
   result = _malloc_internal_nolock (size);
   UNLOCK ();
 
+  debug_malloc (result, size);
   return result;
 }
 
diff --git i/src/regex.c w/src/regex.c
index 164eb46..861b800 100644
--- i/src/regex.c
+++ w/src/regex.c
@@ -828,6 +828,7 @@ extract_number_and_incr (re_char **source)
    interactively.  And if linked with the main program in `main.c' and
    the other test files, you can run the already-written tests.  */
 
+#define DEBUG
 #ifdef DEBUG
 
 /* We use standard I/O for debugging.  */
@@ -838,6 +839,13 @@ extract_number_and_incr (re_char **source)
 
 static int debug = -100000;
 
+static void debug_spot (int fail_stack_avail, const char*string1, const char*string2)
+{
+  extern void r_alloc_check (void);
+  //r_alloc_check ();
+  fail_stack_avail++;
+}
+
 # define DEBUG_STATEMENT(e) e
 # define DEBUG_PRINT(...) if (debug > 0) printf (__VA_ARGS__)
 # define DEBUG_COMPILES_ARGUMENTS
@@ -1172,16 +1180,31 @@ print_double_string (re_char *where, re_char *string1, ssize_t size1,
     printf ("(null)");
   else
     {
+      int i;
       if (FIRST_STRING_P (where))
 	{
-	  for (this_char = where - string1; this_char < size1; this_char++)
-	    putchar (string1[this_char]);
+	  for (i = 0, this_char = where - string1; this_char < size1; i++, this_char++)
+            {
+              if (i > 20)
+                {
+                  putchar ('.'); putchar ('.'); putchar ('.');
+                  break;
+                }
+              putchar (string1[this_char]);
+            }
 
 	  where = string2;
 	}
 
-      for (this_char = where - string2; this_char < size2; this_char++)
-	putchar (string2[this_char]);
+      for (i = 0, this_char = where - string2; this_char < size2; i++, this_char++)
+        {
+          if (i > 20)
+            {
+              putchar ('.'); putchar ('.'); putchar ('.');
+              break;
+            }
+          putchar (string2[this_char]);
+        }
     }
 }
 
@@ -1533,6 +1556,7 @@ while (REMAINING_AVAIL_SLOTS <= space) {				\
      of 0 + -1 isn't done as unsigned.  */				\
   									\
   DEBUG_STATEMENT (nfailure_points_pushed++);				\
+  if (debug > 0) debug_spot((fail_stack).avail, string1,string2);              \
   DEBUG_PRINT ("\nPUSH_FAILURE_POINT:\n");				\
   DEBUG_PRINT ("  Before push, next avail: %zd\n", (fail_stack).avail);	\
   DEBUG_PRINT ("			size: %zd\n", (fail_stack).size);\