From: Chris J Arges <carges@cloudflare.com>
Date: Wed, 8 Apr 2026 19:10:47 +0000 (-0500)
Subject: net: Add net_cookie to Dead loop messages
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b258cba1e05df758e4e99a0e374da3e044618475;p=thirdparty%2Fkernel%2Flinux.git

net: Add net_cookie to Dead loop messages

Network devices can have the same name within different network namespaces.
To help distinguish these devices, add the net_cookie value which can be
used to identify the netns.

Signed-off-by: Chris J Arges <carges@cloudflare.com>
Link: https://patch.msgid.link/20260408191056.1036330-1-carges@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index e7bc95cbd1fa..ccc4418b3163 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4894,8 +4894,9 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
 	} else {
 		/* Recursion is detected! It is possible unfortunately. */
 recursion_alert:
-		net_crit_ratelimited("Dead loop on virtual device %s, fix it urgently!\n",
-				     dev->name);
+		net_crit_ratelimited("Dead loop on virtual device %s (net %llu), fix it urgently!\n",
+				     dev->name, dev_net(dev)->net_cookie);
+
 		rc = -ENETDOWN;
 	}
 
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index f430d6f0463e..2667f53482bd 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -60,8 +60,8 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 
 	if (unlikely(dev_recursion_level() > IP_TUNNEL_RECURSION_LIMIT)) {
 		if (dev) {
-			net_crit_ratelimited("Dead loop on virtual device %s, fix it urgently!\n",
-					     dev->name);
+			net_crit_ratelimited("Dead loop on virtual device %s (net %llu), fix it urgently!\n",
+					     dev->name, dev_net(dev)->net_cookie);
 			DEV_STATS_INC(dev, tx_errors);
 		}
 		ip_rt_put(rt);