[Samba] Winbindd (tdb_chainlock_with_timeout_internal: alarm (40) timed out for key)

[L.P.H. van Belle]

It looks like : 

https://bugzilla.samba.org/show_bug.cgi?id=11962 

> 
> a. What is mutex.tdb, what is its purpose?
A Mutex is a mutually exclusive flag. It acts as a gate keeper to a section of code allowing one thread in and blocking access to all others.

> 
> b. why "mutex grab failed" started appearing in messages, what can be
> the probable reasons?

Server to slow, dns responcing to slow, locking bugs in tdb. 
Things like that. 

> 
> Is pre-authentication failed related to locking failure of mutex.tdb?
Might be. 


> 
> 
> Dec 15 12:49:52 abc winbindd[30467]: [2018/12/15 12:49:52.764924, 0]
> ../source3/libsmb/cliconnect.c:1921(cli_session_setup_spnego_send)
> 
> Dec 15 12:49:52 abc winbindd[30467]: Kinit for ABC$@TYP.ORG
> <mailto:AKLRHEMPDP001$@ENTERPRISENET.ORG> to access
> cifs/xyz.fgb.net at xyz.NET
> <mailto:cifs/CVGWINDOMP011.securityroot.net at SECURITYROOT.NET> failed:
> Preauthentication failed
> 
> ......


I suggest, test on one server my 4.8 package for jessie. 
If the 4.2 to 4.8 step is too big for you, choose a lower version. 
Info here:  https://apt.van-belle.nl/ 

Read : http://downloads.van-belle.nl/samba4/Upgrade-info.txt 
The most needed changes for smb.conf are summerized ni that file. 

And good to see redhat users use debian and ubuntu. ;-) 


Greetz, 

Louis