Re: Returned mail: see transcript for details

[Wolfram Gloger]

> If you allocate enough memory so that eventually malloc would normally return
> NULL because it can't allocate any more memory, the current version of malloc
> from cvs will cause a segmentation violation (on systems that trap access to
> NULL).  This is due to the fact that new_heap returns NULL when it can't
> allocate a new heap.  The January 29th rewrite of malloc introduced the bug.

Thanks, this was a copy'n'paste error with respect to braces, AFAICS.

The patch below doesn't add an extra return path and is therefore more
in line with Lea's original sources.

Regards,
Wolfram.

2002-06-11  Wolfram Gloger  <address@hidden>

        * malloc/malloc.c: Fix error path when new_heap() returns
        NULL.  Reported by Michael Meissner <address@hidden>.

--- malloc.c    2002/05/12 21:16:52     1.9
+++ malloc.c    2002/06/11 09:33:59
@@ -2786,20 +2786,17 @@
 #endif
       set_head(old_top, (((char *)old_heap + old_heap->size) - (char *)old_top)
               | PREV_INUSE);
-    } else {
-      /* A new heap must be created. */
-      heap = new_heap(nb + (MINSIZE + sizeof(*heap)), mp_.top_pad);
-      if(heap) {
-       heap->ar_ptr = av;
-       heap->prev = old_heap;
-       av->system_mem += heap->size;
-       arena_mem += heap->size;
+    }
+    else if ((heap = new_heap(nb + (MINSIZE + sizeof(*heap)), mp_.top_pad))) {
+      /* Use a newly allocated heap.  */
+      heap->ar_ptr = av;
+      heap->prev = old_heap;
+      av->system_mem += heap->size;
+      arena_mem += heap->size;
 #if 0
-       if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > 
max_total_mem)
-         max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
+      if((unsigned long)(mmapped_mem + arena_mem + sbrked_mem) > max_total_mem)
+       max_total_mem = mmapped_mem + arena_mem + sbrked_mem;
 #endif
-      }
-
       /* Set up the new top.  */
       top(av) = chunk_at_offset(heap, sizeof(*heap));
       set_head(top(av), (heap->size - sizeof(*heap)) | PREV_INUSE);