[PATCH net-next 1/2] net: dropreason: add SKB_DROP_REASON_RECURSION_LIMIT

[Eric Dumazet <edumazet@google.com>]

ip[6]tunnel_xmit() can drop packets if a too deep recursion level
is detected.

Add SKB_DROP_REASON_RECURSION_LIMIT drop reason.

We will use this reason later in __dev_queue_xmit().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/net/dropreason-core.h | 3 +++
 include/net/ip6_tunnel.h      | 2 +-
 net/ipv4/ip_tunnel_core.c     | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h
index 5c8c2eb3d2c5b038683b78952106e374cf3b68d1..de61dd5dbfd9dc7d91d22d79a510d42fb69eb60a 100644
--- a/include/net/dropreason-core.h
+++ b/include/net/dropreason-core.h
@@ -123,6 +123,7 @@
 	FN(PFMEMALLOC)	\
 	FN(PSP_INPUT)			\
 	FN(PSP_OUTPUT)			\
+	FN(RECURSION_LIMIT)		\
 	FNe(MAX)
 
 /**
@@ -582,6 +583,8 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_PSP_INPUT,
 	/** @SKB_DROP_REASON_PSP_OUTPUT: PSP output checks failed */
 	SKB_DROP_REASON_PSP_OUTPUT,
+	/** @SKB_DROP_REASON_RECURSION_LIMIT: Dead loop on virtual device. */
+	SKB_DROP_REASON_RECURSION_LIMIT,
 	/**
 	 * @SKB_DROP_REASON_MAX: the maximum of core drop reasons, which
 	 * shouldn't be used as a real 'reason' - only for tracing code gen
diff --git a/include/net/ip6_tunnel.h b/include/net/ip6_tunnel.h
index 359b595f1df93663b3e32c006d936427e8c8b20c..b99805ee2fd14bef6c7bc4daa6e8dfbc34984e4e 100644
--- a/include/net/ip6_tunnel.h
+++ b/include/net/ip6_tunnel.h
@@ -162,7 +162,7 @@ static inline void ip6tunnel_xmit(struct sock *sk, struct sk_buff *skb,
 					     dev->name);
 			DEV_STATS_INC(dev, tx_errors);
 		}
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_RECURSION_LIMIT);
 		return;
 	}
 
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 5683c328990f49df2954af9d890b5f24150caeb2..f430d6f0463e7ab5761e98047a866d304a49abb2 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -65,7 +65,7 @@ void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 			DEV_STATS_INC(dev, tx_errors);
 		}
 		ip_rt_put(rt);
-		kfree_skb(skb);
+		kfree_skb_reason(skb, SKB_DROP_REASON_RECURSION_LIMIT);
 		return;
 	}
 
-- 
2.53.0.880.g73c4285caa-goog