[linux-lvm] LVM2 tools infinite loop if "sg" driver is loaded

["Kevin P. Fleming" <kpfleming backtobasicsmgmt com>]

I just set up some new systems, and loaded both the "sd" and "sg" 
drivers, so I can access their SCSI disks and the SCSI backplane (with 
monitoring software).

However, I find that if the sg driver is loaded, the LVM2 tools 
(LVM2.2.00.22) get stuck in an infinite loop scanning the /sys hierarchy 
(witnessed using strace):

/sys/block/sda/device/generic/device/generic/device...

Removing the sg driver from the kernel is a workaround, but I'd like to 
be able to add it back at some point.