Comment 3 for bug 1559784

modinfo zfcp; for i in {1..1000}; do echo "Try $i"; modprobe zfcp; lsmod | grep -q zfcp && echo ok-here; rmmod zfcp; lsmod | grep zfcp || echo ok-gone; done
filename: /lib/modules/4.4.0-15-generic/kernel/drivers/s390/scsi/zfcp.ko
license: GPL
description: FCP HBA driver
author: IBM Deutschland Entwicklung GmbH - <email address hidden>
srcversion: 342AF26FBC6A761648C34AB
alias: ccw:t1731m03dt1732dm04*
alias: ccw:t1731m03dt1732dm03*
depends: qdio,scsi_transport_fc
intree: Y
vermagic: 4.4.0-15-generic SMP mod_unload modversions
parm: queue_depth:Default queue depth for new SCSI devices (uint)
parm: dif:Enable DIF/DIX data integrity support (bool)
parm: allow_lun_scan:For NPIV, scan and attach all storage LUNs (bool)
parm: datarouter:Enable hardware data router support (default on) (bool)
parm: no_auto_port_rescan:no automatic port_rescan (default off) (bool)
parm: port_scan_backoff:upper limit of port scan random backoff in msecs (default 500) (uint)
parm: port_scan_ratelimit:minimum interval between port scans in msecs (default 60000) (uint)
parm: dbfsize:number of pages for each debug feature area (default 4) (uint)
parm: dbflevel:log level for each debug feature area (default 3, range 0..6) (uint)
parm: device:specify initial device (charp)
Try 1
ok-here
ok-gone
Try 2
ok-here
ok-gone
[...]

you get the idea, worked until 1000.

Therefore the bug is invalid with a recent kernel