[Samba] winbindd completely stopped responding

[Christian Huldt]

I have a samba3 server (ubuntu, 3.4.7) joined to a samba4 that has been working very nicely but today I got errors:

net ads testjoin 
	says the join is OK, but 
wbinfo -t

says
	checking the trust secret via RPC calls failed
	Could not check secret


and winbind logs on that machine (samba3) says:
lsa_lookupsids call failed with NT_STATUS_NO_MEMORY - retrying...

However, another samba3 machine that not really used works just fine...

I finally found two stuck winbind processes on the failing samba3 machine, after killing them and restarting winbind 
everthing was working perfectly again, but I would like to understand the problem better.

What would cause winbindd to completely stop responding after running just fine for days?

Christian Huldt