netdev - [PATCH 03/13] netfilter: nf_flow_table: fix netdev refcnt leak

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Date:   Mon, 13 May 2019 11:56:20 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 03/13] netfilter: nf_flow_table: fix netdev refcnt leak

From: Taehee Yoo <ap420073@...il.com>

flow_offload_alloc() calls nf_route() to get a dst_entry. Internally,
nf_route() calls ip_route_output_key() that allocates a dst_entry and
holds it. So, a dst_entry should be released by dst_release() if
nf_route() is successful.

Otherwise, netns exit routine cannot be finished and the following
message is printed:

[  257.490952] unregister_netdevice: waiting for lo to become free. Usage count = 1

Fixes: ac2a66665e23 ("netfilter: add generic flow table infrastructure")
Signed-off-by: Taehee Yoo <ap420073@...il.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nft_flow_offload.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/nft_flow_offload.c b/net/netfilter/nft_flow_offload.c
index 8968c7f5a72e..69d7a8439c7a 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -112,6 +112,7 @@ static void nft_flow_offload_eval(const struct nft_expr *expr,
 	if (ret < 0)
 		goto err_flow_add;
 
+	dst_release(route.tuple[!dir].dst);
 	return;
 
 err_flow_add:
-- 
2.11.0