Panic after hung rsync, probably zfs related

[Kris Kennaway]

Xin LI wrote:
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> Ben Stuyts wrote:
> | Hi,
> |
> | While doing an rsync from a zfs filesystem to an external usb hd (also
> | zfs), the rsync processes hung in zfs state. I could not kill these
> | processes, although the rest of the server seemingly continued to run
> | fine. The reboot command did not work. Next I tried a shutdown now
> | command. This caused a panic:
> 
> Sound like you somehow run out of memory, there is an known issue with
> ZFS which causes livelock when there is memory pressure.  Which rsync
> version are you using?  With rsync 3.x the memory usage would drop
> drastically which would help to prevent this from happening.

This isn't known to cause a double fault though.  Unfortunately we 
probably need more information than was available in order to proceed.

Kris