Anything depending on the output of 'sysctl -a' or 'sysctl kstat.zfs.misc.dbufs' will effectively hang 'forever' on my system, and reportedly others too. The system in question is running a poudriere jail, which builds a few hundred packages every night.
System is a 8-core 256GB system; resource congestion is not an issue.
E.g. Puppet will be useless on this system, since 'sysctl -a' is run during fact collection.
Suggestion: Do not gather/output kstat.zfs.misc.dbufs unless specifically requested.
# time sysctl kstat.zfs.misc.dbufs | wc
0 0 0
186084 6885040 54442005
Is anything happening here? This breaks various applications that rely on sysctl -a output, including Puppet (configuration management).
This is going to be fixed, but it is waiting on some other things that need to land first.