I edited /etc/group to add myself to another group, raising my total
to 33, and I was no longer able to log in. /var/log/secure reported
"fatal: getgroups: Invalid argument". Some googling revealed the
source of the problem, that getgroups returns EINVAL when the number
of groups exceeds a kernel limit (NGROUPS_MAX in
I'm not sure what the best fix is, but one shouldn't be locked out of
logging in when another group is added to one's list. sshd should fail
in a more graceful way, for example allowing the login but without all
supplmentary groups available, and a warning issued to the login
terminal and the syslog.
See also bug 145492.
It seems to be working fine in FC3.