Zpool with L2ARC hangs whole system

[Karli Sjöberg]

Hi Steven!

Seeing as you were involved in:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=187594

I thought that you may interested to know that I´ve tested upgrading a
virtual machine to 10.1-RELEASE with these patches applied:
https://svnweb.freebsd.org/base?view=revision&revision=272875

And I can still hang a machine reliably just by adding a cache drive to
the pool. Removing the cache makes it stable again. It´s not something
new, this plague has been haunting us since 9.2-RELEASE and I would be
so thankful if we could finally start using the cache drives with
confidence again.

I´ve filed a new bug, in case it´s not really the same issue as in
187594:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197164

If there´s anything you need to test or whatever, I´m all for it, this
VM is at your complete disposal.

Best Regards
Karli Sjöberg