That (and traversals in case of umount .) should be done before
complete_walk().  Either a braino or mismerge damage on queue
reorders - either way, I should've spotted that much earlier.
Fucked-up-by: NAl Viro <viro@zeniv.linux.org.uk>
X-Paperbag: Brown
Fixes: 161aff1d "LOOKUP_MOUNTPOINT: fold path_mountpointat() into path_lookupat()"
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>