The bug that upstream commit c6c7f2a84da45 ("nfsd: Ensure knfsd shuts down when the "nfsd" pseudofs is unmounted") fixes in kernel v5.13 exists in kernel v5.4 too. That is, knfsd threads are left behind once the nfsd pseudofs is unmounted, e.g. when the container is killed. I backported the patch to kernel v5.4, and tested it. Trond Myklebust (1): nfsd: Ensure knfsd shuts down when the "nfsd" pseudofs is unmounted fs/nfsd/netns.h | 6 +++--- fs/nfsd/nfs4state.c | 8 +------- fs/nfsd/nfsctl.c | 14 ++------------ fs/nfsd/nfsd.h | 3 +-- fs/nfsd/nfssvc.c | 35 ++++++++++++++++++++++++++++++++++- 5 files changed, 41 insertions(+), 25 deletions(-) -- 2.30.2