xfrm: fix a race in xfrm_state_lookup_byspi

The returned xfrm_state should be hold before unlock xfrm_state_lock,
otherwise the returned xfrm_state maybe be released.

Fixes: c454997e6[{pktgen, xfrm} Introduce xfrm_state_lookup_byspi..]
Cc: Fan Du <fan.du@intel.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Acked-by: Fan Du <fan.du@intel.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index f5e39e35d73a..96688cd0f6f1 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -927,8 +927,8 @@ struct xfrm_state *xfrm_state_lookup_byspi(struct net *net, __be32 spi,
                         x->id.spi != spi)
                         continue;
 
-                spin_unlock_bh(&net->xfrm.xfrm_state_lock);
                 xfrm_state_hold(x);
+                spin_unlock_bh(&net->xfrm.xfrm_state_lock);
                 return x;
         }
         spin_unlock_bh(&net->xfrm.xfrm_state_lock);