When use-gss-proxy is set to 1, write_gssp will lead to 2 get_net calls
in gssp_rpc_create, the paired put_net calls are supposed to be made
in rpcsec_gss_net_ops->exit i.e. rpcsec_gss_exit_net, but this will
never happen because rpcsec_gss_exit_net (via ops_exit_list) is called
by cleanup_net and cleanup_net will never run unless net->count becomes
0, since the paired put_net calls of gssp_rpc_create are not made yet,
net->count cannot drop to 0. This is dead lock situation.
This fix introduced a new method i.e. evict in struct proc_ns_operations,
which is called in nsfs_evict, moving rpcsec_gss_exit_net into the code
path of nsfs_evict gives it a chance to run.
Signed-off-by: Wenbin Zeng <wenbinzeng@tencent.com>
Wenbin Zeng