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* [net  1/1] tipc: lock wakeup & inputq at tipc_link_reset()
@ 2018-09-25 20:09 Jon Maloy
  2018-09-26  3:49 ` David Miller
  0 siblings, 1 reply; 2+ messages in thread
From: Jon Maloy @ 2018-09-25 20:09 UTC (permalink / raw)
  To: davem, netdev
  Cc: gordan.mihaljevic, tung.q.nguyen, hoang.h.le, jon.maloy,
	canh.d.luu, ying.xue, tipc-discussion

From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>

In tipc_link_reset() we copy the wakeup queue to input queue using
skb_queue_splice_init(link->wakeupq, link->inputq).
This is performed without holding any locks. The lists might be
simultaneously be accessed by other cpu threads in tipc_sk_rcv(),
something leading to to random missing packets.

Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
---
 net/tipc/link.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/tipc/link.c b/net/tipc/link.c
index b1f0bee..26cc033 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -841,9 +841,14 @@ void tipc_link_reset(struct tipc_link *l)
 	l->in_session = false;
 	l->session++;
 	l->mtu = l->advertised_mtu;
+	spin_lock_bh(&l->wakeupq.lock);
+	spin_lock_bh(&l->inputq->lock);
+	skb_queue_splice_init(&l->wakeupq, l->inputq);
+	spin_unlock_bh(&l->inputq->lock);
+	spin_unlock_bh(&l->wakeupq.lock);
+
 	__skb_queue_purge(&l->transmq);
 	__skb_queue_purge(&l->deferdq);
-	skb_queue_splice_init(&l->wakeupq, l->inputq);
 	__skb_queue_purge(&l->backlogq);
 	l->backlog[TIPC_LOW_IMPORTANCE].len = 0;
 	l->backlog[TIPC_MEDIUM_IMPORTANCE].len = 0;
-- 
2.1.4

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [net 1/1] tipc: lock wakeup & inputq at tipc_link_reset()
  2018-09-25 20:09 [net 1/1] tipc: lock wakeup & inputq at tipc_link_reset() Jon Maloy
@ 2018-09-26  3:49 ` David Miller
  0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2018-09-26  3:49 UTC (permalink / raw)
  To: jon.maloy; +Cc: netdev, tipc-discussion

From: Jon Maloy <jon.maloy@ericsson.com>
Date: Tue, 25 Sep 2018 22:09:10 +0200

> From: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
> 
> In tipc_link_reset() we copy the wakeup queue to input queue using
> skb_queue_splice_init(link->wakeupq, link->inputq).
> This is performed without holding any locks. The lists might be
> simultaneously be accessed by other cpu threads in tipc_sk_rcv(),
> something leading to to random missing packets.
> 
> Signed-off-by: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>

Applied.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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