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([2a09:bac6:bf21:2e28::499:49]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-7dc098578c3sm1979035a34.25.2026.04.08.12.11.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 08 Apr 2026 12:11:20 -0700 (PDT) From: Chris J Arges To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern Cc: kernel-team@cloudflare.com, Chris J Arges , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2] net: Add net_cookie to Dead loop messages Date: Wed, 8 Apr 2026 14:10:47 -0500 Message-ID: <20260408191056.1036330-1-carges@cloudflare.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- 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