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Subject[PATCH 4.9 29/33] lockd: lost rollback of set_grace_period() in lockd_down_net()
4.9-stable review patch.  If anyone has any objections, please let me know.


From: Vasily Averin <>

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 <>
Signed-off-by: J. Bruce Fields <>
Cc: Ben Hutchings <>
Signed-off-by: Greg Kroah-Hartman <>

fs/lockd/svc.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -274,6 +274,8 @@ static void lockd_down_net(struct svc_se
if (ln->nlmsvc_users) {
if (--ln->nlmsvc_users == 0) {
+ 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);

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