[PATCH net-next v2] net: Add net_cookie to Dead loop messages

[PATCH net-next v2] net: Add net_cookie to Dead loop messages

[Chris J Arges]

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>
---
v2: rebased on net-next
---
 net/core/dev.c            | 5 +++--
 net/ipv4/ip_tunnel_core.c | 4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 5a31f9d2128c..3c752ba3aa29 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4886,8 +4886,9 @@ 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);
-- 
2.43.0