[PATCH 5.1 078/155] netfilter: nf_flow_table: fix netdev refcnt leak

Greg Kroah-Hartman
2019-06-13T16:03:45Z

[ Upstream commit 26a302afbe328ecb7507cae2035d938e6635131b ]

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@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.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 6e6b9adf7d38..ff50bc1b144f 100644
--- a/net/netfilter/nft_flow_offload.c
+++ b/net/netfilter/nft_flow_offload.c
@@ -113,6 +113,7 @@ 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:
--
2.20.1