From 25d3c3143a32685b149e576388cf1b886a89acb2 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 29 Sep 2010 13:23:09 -0700
Subject: [PATCH] --- yaml --- r: 214799 b: refs/heads/master c:
 745e20f1b626b1be4b100af5d4bf7b3439392f8f h: refs/heads/master i:   214797:
 195c6a191689afec0df525baf1d5475da8747f00   214795:
 f7c271624995202302b51ae54c20dd0ec2aba10a   214791:
 6ad6af467154525b5078bc16d084c5a61c7fc19f   214783:
 37746227463dab6ac8c840dc0b23c7dd12723a59 v: v3

---
 [refs]               |  2 +-
 trunk/net/core/dev.c | 12 +++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/[refs] b/[refs]
index 2a29a74fe985..b2c520895b0b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ab79ad14a2d51e95f0ac3cef7cd116a57089ba82
+refs/heads/master: 745e20f1b626b1be4b100af5d4bf7b3439392f8f
diff --git a/trunk/net/core/dev.c b/trunk/net/core/dev.c
index 48ad47f402ad..50daccad6a53 100644
--- a/trunk/net/core/dev.c
+++ b/trunk/net/core/dev.c
@@ -2177,6 +2177,9 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q,
 	return rc;
 }
 
+static DEFINE_PER_CPU(int, xmit_recursion);
+#define RECURSION_LIMIT 3
+
 /**
  *	dev_queue_xmit - transmit a buffer
  *	@skb: buffer to transmit
@@ -2242,10 +2245,15 @@ int dev_queue_xmit(struct sk_buff *skb)
 
 		if (txq->xmit_lock_owner != cpu) {
 
+			if (__this_cpu_read(xmit_recursion) > RECURSION_LIMIT)
+				goto recursion_alert;
+
 			HARD_TX_LOCK(dev, txq, cpu);
 
 			if (!netif_tx_queue_stopped(txq)) {
+				__this_cpu_inc(xmit_recursion);
 				rc = dev_hard_start_xmit(skb, dev, txq);
+				__this_cpu_dec(xmit_recursion);
 				if (dev_xmit_complete(rc)) {
 					HARD_TX_UNLOCK(dev, txq);
 					goto out;
@@ -2257,7 +2265,9 @@ int dev_queue_xmit(struct sk_buff *skb)
 				       "queue packet!\n", dev->name);
 		} else {
 			/* Recursion is detected! It is possible,
-			 * unfortunately */
+			 * unfortunately
+			 */
+recursion_alert:
 			if (net_ratelimit())
 				printk(KERN_CRIT "Dead loop on virtual device "
 				       "%s, fix it urgently!\n", dev->name);