/usr/sbin/winbindd:6:__GI___pthread_mutex_lock:allrecord_mutex_lock:tdb_mutex_allrecord_lock:tdb_allrecord_lock:tdb_lockall

The Ubuntu Error Tracker has been receiving reports about a problem regarding samba. This problem was most recently seen with package version 2:4.3.11+dfsg-0ubuntu0.16.04.1, the problem page at https://errors.ubuntu.com/problem/e9ad57c4eacc4ed4f54e6520cfa0e55f8b2057c1 contains more details, including versions of packages affected, stacktrace or traceback, and individual crash reports.
If you do not have access to the Ubuntu Error Tracker you can request it at http://forms.canonical.com/reports/.