usb/121168: Kernel panic when try to unmount removed usbdrive

[Hans Petter Selasky]

On Thursday 28 February 2008, Rashid N. Achilov wrote:
> On Thursday 28 February 2008, Octavian wrote:
> > >How-To-Repeat:
> >
> > mount_msdosfs /dev/da0s1 /mnt/usbdrive/
> > cd /mnt/usbdrive
> > ---(remove usbdrive from port)
> > umount -f /mnt/usbdrive
> >
> > kernel panic...
>
> O, God! Kernel panic when extracted MSDOS device without unmounting them
> exist in FreeBSD till 2.2.5 version *ROFL* That ancient days, when you
> mount floppy and extract without unmounting, kernel panics... This days
> flopies were dead. But their place now occupied by USB Flash drives, which
> you can easily extract without unmounting. And "I'll back" :-) - when you
> extract mounted flashdrive, kernel panics again...
>
> For me, USB subsystem in FreeBSD works terrible. Inserting USB Flashdrive
> can hang up or reboot system, inserting digital camera can freeze system
> until USB cord will extracted, boot with inserted USB Flash dumps BTX
> "registers over", USB wireless mices, bought with wireless keyboards, does
> not works... It's too sad...

What you are telling us is all well known and I suspect someone will fix this 
issue eventually.

BTW: The FAT32 file system which is used on most memory sticks does not handle 
surprise removal very well.

--HPS