SUMMARY

HOME on nfs share. /bin/plasmashell freezes there:

#3  0x00007f5318ad8705 in KDirWatchPrivate::useFAM (this=this@entry=0x247fa60, e=e@entry=0x2934c50)
    at /usr/src/debug/kcoreaddons-5.42.0/src/lib/io/kdirwatch.cpp:696
696             QThread::msleep(50);
(gdb) li
691         do {
692           famEventReceived();
693           if (startedFAMMonitor && !e->m_famReportedSeen) {
694             // 50 is ~half the time it takes to setup a watch.  If gamin's latency
695             // gets better, this can be reduced.
696             QThread::msleep(50);
697           }
698         } while (startedFAMMonitor &&!e->m_famReportedSeen);

Changing in gdb: set e->m_famReportedSeen=1
releases plasmashell from freeze.