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Date: Wed, 8 Jun 2005 17:24:07 -0700
From: Chris Wright <chrisw@osdl.org>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: Justin Forbes <jmforbes@linuxtx.org>,
       Zwane Mwaikambo <zwane@arm.linux.org.uk>,
       "Theodore Ts'o" <tytso@mit.edu>, Randy Dunlap <rdunlap@xenotime.net>,
       Chuck Wolber <chuckw@quantumlinux.com>, torvalds@osdl.org,
       akpm@osdl.org, alan@lxorguk.ukuu.org.uk, shemminger@osdl.org
Subject: [patch 09/09] [PKT_SCHED]: netem: duplication fix
Message-ID: <20050609002407.GP13152@shell0.pdx.osdl.net>
References: <20050608234637.GG13152@shell0.pdx.osdl.net>
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Netem duplication can cause infinite loop in qdisc_run
because the qlen of the parent qdisc is not affected by the duplication.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Chris Wright <chrisw@osdl.org>

Index: 2.6.11.11-net/net/sched/sch_netem.c
===================================================================
--- 2.6.11.11-net.orig/net/sched/sch_netem.c
+++ 2.6.11.11-net/net/sched/sch_netem.c
@@ -184,10 +184,15 @@ static int netem_enqueue(struct sk_buff 
 	/* Random duplication */
 	if (q->duplicate && q->duplicate >= get_crandom(&q->dup_cor)) {
 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
-
-		pr_debug("netem_enqueue: dup %p\n", skb2);
-		if (skb2)
-			delay_skb(sch, skb2);
+		if (skb2) {
+			struct Qdisc *rootq = sch->dev->qdisc;
+			u32 dupsave = q->duplicate; 
+
+			/* prevent duplicating a dup... */
+			q->duplicate = 0;
+			rootq->enqueue(skb2, rootq);
+			q->duplicate = dupsave;
+		}
 	}
 
 	/* If doing simple delay then gap == 0 so all packets