Comment 41 for bug 790538

Revision history for this message
Chris Siebenmann (cks) wrote :

Not all aspects of this PAM failure can be fixed easily, since daemons
other than cron were also affected. Cron can be restarted without user
impact, but something like xdm cannot be.

(Since we got hurt by the xdm issue, not by the cron issue, I am
rather sensitive about this.)

I personally think that we were quite lucky that the Ubuntu sshd was not
affected by this, although it uses PAM. (I am not sure why it was unaffected,
since sshd has libpam loaded and requires pam_env.so in a normal Ubuntu
config.)

I also hope that Ubuntu will conduct a real root cause analysis on this.
'Cron locked up after a PAM upgrade' is only the surface problem and
addressing and detecting just it would be only addressing the most
obvious symptom of the real problem. The real problem was 'a PAM
update was not ABI compatible'; the broken processes were simply
a symptom of this. I would like Ubuntu to change things so that they
detect this if it happens again, not merely instances of the root
cause where cron helpfully locks up.