[IRDA]: Fix races between IRNET and PPP.

- Prevent sending status event to dead/kfree sockets
- Disable PPP access before deregistration
  PPP deregistration might sleep -> race condition

net/irda/irnet/irnet_ppp.c

@@ -512,8 +512,8 @@ dev_irnet_close(struct inode *	inode,
   if(ap->ppp_open)
     {
       DERROR(FS_ERROR, "Channel still registered - deregistering !\n");
-      ppp_unregister_channel(&ap->chan);
       ap->ppp_open = 0;
+      ppp_unregister_channel(&ap->chan);
     }
 
   kfree(ap);
@@ -651,10 +651,12 @@ dev_irnet_ioctl(struct inode *	inode,
 	  DEBUG(FS_INFO, "Exiting PPP discipline.\n");
 	  /* Disconnect from the generic PPP layer */
 	  if(ap->ppp_open)
+	    {
+	      ap->ppp_open = 0;
 	      ppp_unregister_channel(&ap->chan);
+	    }
 	  else
 	    DERROR(FS_ERROR, "Channel not registered !\n");
-	  ap->ppp_open = 0;
 	  err = 0;
 	}
       break;

net/irda/irttp.c

@@ -968,6 +968,10 @@ void irttp_status_indication(void *instance,
 	ASSERT(self != NULL, return;);
 	ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
 
+	/* Check if client has already closed the TSAP and gone away */
+	if (self->close_pend)
+		return;
+
 	/*
 	 *  Inform service user if he has requested it
 	 */
@@ -1603,7 +1607,7 @@ void irttp_do_data_indication(struct tsap_cb *self, struct sk_buff *skb)
 {
 	int err;
 
-	/* Check if client has already tried to close the TSAP */
+	/* Check if client has already closed the TSAP and gone away */
 	if (self->close_pend) {
 		dev_kfree_skb(skb);
 		return;