[patch 18/46] pkt_sched: sch_htb: Fix deadlock in hrtimerstriggered by HTB

[Greg KH]

2.6.28-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Jarek Poplawski <jarkao2@xxxxxxxxx>

[ Upstream commit: none

  This is a quick fix for -stable purposes.  Upstream fixes these
  problems via a large set of invasive hrtimer changes.  ]

Most probably there is a (still unproven) race in hrtimers (before
2.6.29 kernels), which causes a corruption of hrtimers rbtree. This
patch doesn't fix it, but should let HTB avoid triggering the bug.

Reported-by: Denys Fedoryschenko <denys@xxxxxxxxxxx>
Reported-by: Badalian Vyacheslav <slavon@xxxxxxxxxxxxx>
Reported-by: Chris Caputo <ccaputo@xxxxxxx>
Tested-by: Badalian Vyacheslav <slavon@xxxxxxxxxxxxx>
Signed-off-by: Jarek Poplawski <jarkao2@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/sched/sch_htb.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -924,6 +924,7 @@ static struct sk_buff *htb_dequeue(struc
 		}
 	}
 	sch->qstats.overlimits++;
+	qdisc_watchdog_cancel(&q->watchdog);
 	qdisc_watchdog_schedule(&q->watchdog, next_event);
 fin:
 	return skb;

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