Linux NFS4 server may drop requests, suffer a DoS, or respond to RENEW with NFS4ERR_EXPIRED when lease is not expired due to logging process reading /proc/net/rpc/auth.unix.gid/channel
Issue
- NFS client hung due to NFS server responding to RENEW with NFS4ERR_EXPIRED continuously.
- NFS client hangs during mount or other operation due to logging or other process running as root reading /proc/net/rpc/auth.unix.gid/channel
Environment
- Red Hat Enterprise Linux 6 - 8 (NFS server)
- RHEL6 kernels (all)
- RHEL7 kernels up to at least kernel-3.10.0-1062.el7
- RHEL8 kernels up to at least kernel-4.18.0-80.el8
- NFSv4.0
- a root process reading /proc files including /proc/net/rpc/auth.unix.gid/channel
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