ldap: ping does not return

[Nigel Wade]

Herbert Gasiorowski wrote:
>  From "Re: Latest FC kernel still have SMP bugs?"
> 
> Nigel Wade wrote:
> 
>> Herbert Gasiorowski wrote:
>>
>>> Nigel Wade wrote:
>>>
>>>> Herbert Gasiorowski wrote:
>>>>
>>>>>> I've built the RHEL3 kernel on FC1 and run the system up using 
>>>>>> this. Ordinary ldap requests seem quite happy, but I'm still 
>>>>>> seeing the futex lock problem with nss_ldap. E.g. when I add 
>>>>>> 'hosts: files ldap dns' to /etc/nsswitch.conf I get:
>>>>>>
>>>>>> # strace ping host
>>>>>> munmap(0xb75ff000, 4096)                = 0
>>>>>> uname({sys="Linux", node="hostname", ...}) = 0
>>>>>> futex(0x53e4ec, FUTEX_WAIT, 2, NULL
>>>>>>
>>>>>> Setting LD_ASSUME_KERNEL=2.4.1 cures this particular problem, but 
>>>>>> isn't a solution for a system relying on LDAP for all 
>>>>>> authentication and NSS functions.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> The problem remains in FC2 (Test 3) with the 2.6 kernel!
>>>>>
>>>>> LD_ASSUME_KERNEL=2.4.1 seems to cure at least "ping host"
>>>>>
>>>>>
>>>>
>>>> This is in some way related to nscd.
>>>>
>>>> If nscd isn't running hosts don't resolve using LDAP. AFAIK, nscd 
>>>> should not be compulsory.
>>>>
>>>
>>> Thanks, this seems to solve my problem and finally I managed to 
>>> install nscd!
>>>
>>
>> I do this, but I have to say I don't like it. It's very precarious - 
>> if nscd hangs or crashes for some reason the m/c is unusable. You 
>> can't even login as root at the console to fix nscd if host resolution 
>> is hanging. Eventually pretty much everything hangs.
> 
> 
> Actually it does not solve my problem: I need to use "hosts: files ldap 
> dns"
> in nsswitch.conf, but then again ping never returns and nscd crashes.
> (It only works with "hosts: files dns ldap" and nscd)
> 

I just added a reply in Bugzilla to your report of this.

Here, I can get nscd to work with "host: files ldap dns", but I had to 
restart it after I changed nsswitch.conf.


-- 
Nigel Wade, System Administrator, Space Plasma Physics Group,
             University of Leicester, Leicester, LE1 7RH, UK
E-mail :    nmw at ion.le.ac.uk
Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555