[Bug 1373760] Re: 14.04 hangs with passwd_compat: ldap

[Giuseppe Attardi]

On 9/25/2014 13:55, Robie Basak wrote:
> Thank you for taking the time to report this bug and helping to make
> Ubuntu better.
>
> I don't think this is described in enough detail for a developer to
> begin to look at the problem. I can't tell whether this is a local
> misconfiguration or not, either.
>
> Please could you post steps for a developer to reproduce the problem?
>
> You may find it helpful to read "How to report bugs effectively"
> http://www.chiark.greenend.org.uk/~sgtatham/bugs.html. We'd be grateful
> if you would then provide a more complete description of the problem,
> explain why you believe this is a bug in Ubuntu rather than a problem
> specific to your system, and then change the bug status back to New.
>
> ** Changed in: libnss-ldap (Ubuntu)
>         Status: New => Incomplete
>
I wish I could be more specific.
It took me 10 hours to figure out what was going on, having to boot 
repeatedly the machine each time it hanged.
The configuration I was using worked perfectly well on 12 LTS and the 
only change I made to fix the problem after the upgrade is the one I 
mentioned.
The same thing happened on a second machine which was configured similarly.
So I concluded that this is a situation that may occurr to others as 
well and it could save them some time if they knew a solution.

I could not find relevant documentation about the parameter
     passwd_compat
except that it appears related to Solaris.
I suspect that this is a legacy configuration that has been preserved by 
our system administrators since the time we were using Sun machines in 
our network.
Possibily this parameter creates some conflicts on release 14 that make 
it to hang the machine.
Someone who knows what passwd_compat does should be able to figure out 
the cause.

To replicate the problem it should be enough to configure nsswitch like 
this:

     passwd: compat
     passwd_compat: ldap

After this, try doing add-user and the machine will hang.

Thank you.

prof. Giuseppe Attardi
Università di Pisa

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https://bugs.launchpad.net/bugs/1373760

Title:
  14.04 hangs with passwd_compat: ldap

Status in “libnss-ldap” package in Ubuntu:
  Incomplete

Bug description:
  I did a release upgrade from 12.04.3 to 14.04.1.

  After the upgrade, only local users could log in and any command was very slooow.
  In particular commands like add-user or add-group would never finish.
  Hence some installation commands would hang.

  Removing mentions of ldap in nsswitch.conf seemed to solve the
  problem.

  In the end I discovered that the apparent cause was removing this line
  from nsswitch:

  passwd_compat: ldap

  and using instead

  passwd: compat ldap

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