One of the most common crasher I've seen is removing elements of a data structure while iterating it. Typically:

for (l = list; l != NULL; l = l->next)
  {
    if (cond)
      list = g_list_delete_link (list, l);
  }

or:

g_hash_table_foreach (table, {if (cond) g_hash_table_remove (table, key);}, NULL);

or:

while (g_hash_table_iter_next (&iter, &k, &v))
  {
    if (cond)
      g_hash_table_remove (table, k);
  }

Since it is really common mistake I think the doc of g_hash_table_iter_remove() should be explicit about that case. I _think_ it is safe to this, but I'm not entirely sure:

while (g_hash_table_iter_next (&iter, &k, &v))
  {
    if (cond)
      g_hash_table_iter_remove (&iter);
  }