Comment 70 for bug 1470250

@f-bosch @jsalisbury
I can reproduce the issue consistently within 5~6 hours with a Ubuntu 15.10 VM.

In /var/log/syslog, several minutes before the file system is remounted as read-only, the hv_vss_daemon has stopped working: the daemon just always hangs on the poll() , not receiving freeze/thaw commands from the hv_utils driver at all.

I guess there might be a race condition in the hv_utils.ko driver, so the commands from the host are not received properly, or not forwarded to the daemon properly, so the daemon isn't be woken up.

Trying to track it down.
BTW, Since Ubuntu 15.04's code of the hv_utils driver and the daemon is the same as the upstream Linux, I think the upstream should have the same issue.

BTW, the below message looks like a benign warning -- I get this every time the backup begins, but I think it has nothing to do with the issue here:
[ 967.339810] sd 2:0:0:0: [storvsc] Sense Key : Unit Attention [current]
[ 967.339891] sd 2:0:0:0: [storvsc] Add. Sense: Changed operating definition
[ 967.340111] sd 2:0:0:0: Warning! Received an indication that the operating parameters on this target have changed. The Linux SCSI layer does not automa