Hi,
we observe frequently problems with KRB5 authentication on EOSATLAS which looks like a dead-lock. We have 2050 threads stuck in a KRb5 mutex:

#0  0x0000003ea900d654 in __lll_lock_wait () from /lib64/libpthread.so.0
#1  0x0000003ea9008f4a in _L_lock_1034 () from /lib64/libpthread.so.0
#2  0x0000003ea9008e0c in pthread_mutex_lock () from /lib64/libpthread.so.0
#3  0x00002aba1f8240d6 in XrdSecProtocolkrb5::Authenticate(XrdSecBuffer*, XrdSecBuffer**, XrdOucErrInfo*) () from /usr/lib64/libXrdSeckrb5.so
#4  0x0000000000426223 in XrdXrootdProtocol::do_Auth() ()
#5  0x000000338024f590 in XrdLink::DoIt() () from /usr/lib64/libXrdUtils.so.1