[openib-general] [PATCH] RDMA/iwcm: Memory corruption bug in cm_work_handler

[Krishna Kumar]

Possible memory corruption scenario : after putting the work
entry back on the work_free_list, we call process_event()
which dereferences work->event, which could have been
modified to another value meanwhile.

Patches against 2.6.19-rc4 bits.

Signed-off-by: Krishna Kumar <krkumar2 at in.ibm.com>
---
diff -ruNp org/drivers/infiniband/core/iwcm.c new/drivers/infiniband/core/iwcm.c
--- org/drivers/infiniband/core/iwcm.c	2006-10-09 16:40:04.000000000 +0530
+++ new/drivers/infiniband/core/iwcm.c	2006-10-09 16:52:03.000000000 +0530
@@ -830,7 +830,8 @@ static int process_event(struct iwcm_id_
  */
 static void cm_work_handler(void *arg)
 {
-	struct iwcm_work *work = arg, lwork;
+	struct iwcm_work *work = arg;
+	struct iw_cm_event levent;
 	struct iwcm_id_private *cm_id_priv = work->cm_id;
 	unsigned long flags;
 	int empty;
@@ -843,11 +844,11 @@ static void cm_work_handler(void *arg)
 				  struct iwcm_work, list);
 		list_del_init(&work->list);
 		empty = list_empty(&cm_id_priv->work_list);
-		lwork = *work;
+		levent = work->event;
 		put_work(work);
 		spin_unlock_irqrestore(&cm_id_priv->lock, flags);
 
-		ret = process_event(cm_id_priv, &work->event);
+		ret = process_event(cm_id_priv, &levent);
 		if (ret) {
 			set_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
 			destroy_cm_id(&cm_id_priv->id);