Winbind using 100% CPU

[Dylan Klomparens]

(Re-posting on this email list per Jeremy Allison's request.)

I am trying to figure out why winbind is using 100% CPU on my file server.
I am using Samba version 4.0.4. Everything is fine for a few minutes when I
start winbind, however after a while it begins using 100% CPU. I haven't
been able to narrow down what triggers this CPU usage spike, but I did
attach the GNU debugger to find out what's going on in the process. The
backtrace revealed this information:

#0  0x000000000041cf30 in _talloc_free at plt ()
#1  0x0000000000452320 in winbindd_reinit_after_fork ()
#2  0x00000000004524e6 in fork_domain_child ()
#3  0x0000000000453585 in wb_child_request_trigger ()
#4  0x000000381d2048e2 in tevent_common_loop_immediate () from
/lib64/libtevent.so.0
#5  0x00007fbed6b98e17 in run_events_poll () from /lib64/libsmbconf.so.0
#6  0x00007fbed6b9922e in s3_event_loop_once () from /lib64/libsmbconf.so.0
#7  0x000000381d204060 in _tevent_loop_once () from /lib64/libtevent.so.0
#8  0x000000000042049a in main ()

Apparently it's stuck in the winbindd_reinit_after_fork (and more
specifically the _talloc_free function). This code resides in
$SOURCE_HOME\source3\winbindd\winbindd_dual.c.

Perhaps I have configured Samba incorrectly? Here are the parameters I am
using that have to do with winbind:
idmap config * : backend = nss
idmap config * : range = 1000 - 300000

What are some reasons that winbind is using 100% CPU and how can I resolve
this?