Bug#962254: NFS(v4) broken at 4.19.118-2

[Elliott Mitchell <ehem+debian@m5p.com>]

Package: src:linux
Version: 4.19.118+2
Severity: important

Somewhere between linux-image-4.19.0-8-amd64/4.19.98+1+deb10u1 and
linux-image-4.19.0-9-amd64/4.19.118+2 NFS, in particular v4 got broken.
Mounting an appropriate filesystem became unreliable, and once mounted
behavior is unpredictable.

In particular in the problematic case `umask 022 ; touch foo ; ls -l foo`
yields a -rw-rw-rw- file.

This occurs if *both* the server *and* client are on 4.19.118+2.  I have
confirmed this does NOT occur if the server is on a 4.9 kernel.  I have
also confirmed this does NOT occur if the client is on a 4.9 or
4.19.98+1+deb10u1 kernel.


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