net: check for refcount if pop a stacked dst_entry (8764ab2c) · Commits · 戴 / test

xfrm triggers a warning if dst_pop() drops a refcount on a noref dst. This patch changes dst_pop() to skb_dst_pop(). skb_dst_pop() drops the refcnt only on a refcounted dst. Also we don't clone the child dst_entry, so it is not refcounted and we can use skb_dst_set_noref() in xfrm_output_one(). Signed-off-by:

Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by:

Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

include/net/dst.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -250,11 +250,11 @@ static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev)
		* Linux networking. Thus, destinations are stackable.
		*/

		static inline struct dst_entry dst_pop(struct dst_entry dst)
		static inline struct dst_entry skb_dst_pop(struct sk_buff skb)
		{
		struct dst_entry *child = dst_clone(dst->child);
		struct dst_entry *child = skb_dst(skb)->child;

		dst_release(dst);
		skb_dst_drop(skb);
		return child;
		}

net/xfrm/xfrm_output.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -95,13 +95,13 @@ resume:
		goto error_nolock;
		}

		dst = dst_pop(dst);
		dst = skb_dst_pop(skb);
		if (!dst) {
		XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
		err = -EHOSTUNREACH;
		goto error_nolock;
		}
		skb_dst_set(skb, dst);
		skb_dst_set_noref(skb, dst);
		x = dst->xfrm;
		} while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));

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