diff -ru linux-2.6.22.orig/drivers/md/dm-crypt.c linux-2.6.22/drivers/md/dm-crypt.c
--- linux-2.6.22.orig/drivers/md/dm-crypt.c	2007-08-03 13:01:16.000000000 +0200
+++ linux-2.6.22/drivers/md/dm-crypt.c	2007-08-03 13:02:14.000000000 +0200
@@ -920,6 +920,8 @@
 {
 	struct crypt_config *cc = (struct crypt_config *) ti->private;
 
+        flush_workqueue(_kcryptd_workqueue);
+
 	bioset_free(cc->bs);
 	mempool_destroy(cc->page_pool);
 	mempool_destroy(cc->io_pool);