I removed a USB 2.0 cardbus card, with device still attached by cable. the disk
had not been mounted in user FS space, but had been probed and attached to SCSI
via atapibus/umass mappings. this caused a panic. my memory tells me that even
on 4.2 on vaxen, arbitrary removal of disks was sometimes a bit painful for a
kernel. Is this still true?

Should I have detached the sd* device by removing the USB cable first? Is there
some userspace trick which can make it 'safe' to yank a controller with attached
devices and not panic a kernel?

I have a vestigial fear that I can't remove the cardbus card if I've ever
mounted a disk via that card, which is a bit different. (I remember seeing this
also panic some time ago this year)

-george