lockd: lost rollback of set_grace_period() in lockd_down_net()

commit 3a2b19d1ee5633f76ae8a88da7bc039a5d1732aa upstream.

Commit efda760fe95ea ("lockd: fix lockd shutdown race") is incorrect,
it removes lockd_manager and disarm grace_period_end for init_net only.

If nfsd was started from another net namespace lockd_up_net() calls
set_grace_period() that adds lockd_manager into per-netns list
and queues grace_period_end delayed work.

These action should be reverted in lockd_down_net().
Otherwise it can lead to double list_add on after restart nfsd in netns,
and to use-after-free if non-disarmed delayed work will be executed after netns destroy.

Fixes: efda760fe95e ("lockd: fix lockd shutdown race")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index f04ecfc7ece0c98789161453377890a68094cb34..45e96549ebd2abe550dd579d25c548cd05ddeeea 100644 (file)
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -274,6 +274,8 @@ static void lockd_down_net(struct svc_serv *serv, struct net *net)
        if (ln->nlmsvc_users) {
                if (--ln->nlmsvc_users == 0) {
                        nlm_shutdown_hosts_net(net);
+                       cancel_delayed_work_sync(&ln->grace_period_end);
+                       locks_end_grace(&ln->lockd_manager);
                        svc_shutdown_net(serv, net);
                        dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net);
                }