Commit fb745e9a authored Apr 11, 2013 by David Ward Committed by David S. Miller Apr 12, 2013

net/802/mrp: fix possible race condition when calling mrp_pdu_queue()



(Adapted from a very similar change to net/802/garp.c by Cong Wang.)

mrp_pdu_queue() should ways be called with the applicant spin lock.
mrp_uninit_applicant() only holds the rtnl lock which is not enough;
a race is possible because mrp_rcv() is called in BH context:

	mrp_rcv()
	  |->mrp_pdu_parse_msg()
	    |->mrp_pdu_parse_vecattr()
	      |->mrp_pdu_parse_vecattr_event()
	        |-> mrp_attr_event()
	          |-> mrp_pdu_append_vecattr_event()
	            |-> mrp_pdu_queue()

Cc: Cong Wang <amwang@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David Ward <david.ward@ll.mit.edu>
Acked-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3be8fbab

net/802/mrp.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -870,8 +870,12 @@ void mrp_uninit_applicant(struct net_device dev, struct mrp_application appl)
		* all pending messages before the applicant is gone.
		*/
		del_timer_sync(&app->join_timer);

		spin_lock(&app->lock);
		mrp_mad_event(app, MRP_EVENT_TX);
		mrp_pdu_queue(app);
		spin_unlock(&app->lock);

		mrp_queue_xmit(app);

		dev_mc_del(dev, appl->group_address);

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