caif: Fix race when conditionally taking rtnl lock

Take the RTNL lock unconditionally when calling dev_close.
Taking the lock conditionally may cause race conditions.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 6 deletions

diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 649ebacaf6bc..adbb424403d4 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -139,17 +139,14 @@ static void close_work(struct work_struct *work)
         struct chnl_net *dev = NULL;
         struct list_head *list_node;
         struct list_head *_tmp;
-        /* May be called with or without RTNL lock held */
-        int islocked = rtnl_is_locked();
-        if (!islocked)
-                rtnl_lock();
+
+        rtnl_lock();
         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
                 dev = list_entry(list_node, struct chnl_net, list_field);
                 if (dev->state == CAIF_SHUTDOWN)
                         dev_close(dev->netdev);
         }
-        if (!islocked)
-                rtnl_unlock();
+        rtnl_unlock();
 }
 static DECLARE_WORK(close_worker, close_work);