mem0pool.c:

  Fix a memory corruption bug: in 32-bit computers, every 4 billionth malloc outside innodb_additional_mem_pool_size was mistreated when freeing the memory; this could corrupt the InnoDB additional mem pool and could have caused crashes anywhere, also inside MySQL, or even database corruption! the bug exists also in 3.23 and 4.1; workaround: configure innodb_additional_mem_pool_size big enough

innobase/mem/mem0pool.c

@@ -97,8 +97,6 @@ struct mem_pool_struct{
 /* The common memory pool */
 mem_pool_t*	mem_comm_pool	= NULL;
 
-ulint		mem_out_of_mem_err_msg_count	= 0;
-
 /* We use this counter to check that the mem pool mutex does not leak;
 this is to track a strange assertion failure reported at
 mysql@lists.mysql.com */
@@ -267,8 +265,6 @@ mem_pool_fill_free_list(
 		/* We come here when we have run out of space in the
 		memory pool: */
      
-		mem_out_of_mem_err_msg_count++;
-     
 		return(FALSE);
 	}
 
@@ -460,18 +456,14 @@ mem_area_free(
 	ulint		size;
 	ulint		n;
 	
-	if (mem_out_of_mem_err_msg_count > 0) {
-		/* It may be that the area was really allocated from the
-		OS with regular malloc: check if ptr points within
-		our memory pool */
+	/* It may be that the area was really allocated from the OS with
+	regular malloc: check if ptr points within our memory pool */
 
-		if ((byte*)ptr < pool->buf
-				|| (byte*)ptr >= pool->buf + pool->size) {
+	if ((byte*)ptr < pool->buf || (byte*)ptr >= pool->buf + pool->size) {
 		ut_free(ptr);
 
 		return;
 	}
-	}
 
 	area = (mem_area_t*) (((byte*)ptr) - MEM_AREA_EXTRA_SIZE);