Please pick the following for stable branches 4.4, 4.9, 4.14, 4.19:
commit 9804501fa1228048857910a6bf23e085aade37cc Author: YueHaibing yuehaibing@huawei.com Date: Thu Mar 14 13:47:59 2019 +0800
appletalk: Fix potential NULL pointer dereference in unregister_snap_client
commit c93ad1337ad06a718890a89cdd85188ff9a5a5cc Author: YueHaibing yuehaibing@huawei.com Date: Tue Apr 30 19:34:08 2019 +0800
appletalk: Set error code if register_snap_client failed
The first commit doesn't apply cleanly to 4.4, 4.9, 4.14; you can use the attached backport.
Ben.