xfrm6_tunnel: Fix potential panic when unloading xfrm6_tunnel module

When unloading xfrm6_tunnel module, xfrm6_tunnel_fini directly
frees the xfrm6_tunnel_spi_kmem. Maybe someone has gotten the
xfrm6_tunnel_spi, so need to wait it.

Fixes: 91cc3bb0b04ff("xfrm6_tunnel: RCU conversion")
Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index bc65db782bfb..12cb3aa990af 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -402,6 +402,10 @@ static void __exit xfrm6_tunnel_fini(void)
         xfrm6_tunnel_deregister(&xfrm6_tunnel_handler, AF_INET6);
         xfrm_unregister_type(&xfrm6_tunnel_type, AF_INET6);
         unregister_pernet_subsys(&xfrm6_tunnel_net_ops);
+        /* Someone maybe has gotten the xfrm6_tunnel_spi.
+         * So need to wait it.
+         */
+        rcu_barrier();
         kmem_cache_destroy(xfrm6_tunnel_spi_kmem);
 }