So I just upgraded my ubuntu machine to 9.10 and when I try to change my password with passwd it says,
passwd: Authentication token lock busy
passwd: password unchanged
similarly if I try to su to another user I receive:
su: Authentication failure
I did some research and it looks like most of the time this problem is caused by the file system being in read-only mode vs read-write so I did:
mount -o remount,rw /
but this didn't fix the problem. Any ideas?