kern/104292: system lockup on forced umount of usb-storage device

[Gergely CZUCZY]

>Number:         104292
>Category:       kern
>Synopsis:       system lockup on forced umount of usb-storage device
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Oct 11 08:50:18 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Gergely CZUCZY
>Release:        FreeBSD 6.2-PRERELEASE i386
>Organization:
Harmless Digital Ltd
>Environment:
System: FreeBSD kign.harmless.lan 6.2-PRERELEASE FreeBSD 6.2-PRERELEASE #0: Thu Oct  5 12:49:04 CEST 2006     root at kign.harmless.lan:/usr/obj/usr/src/sys/KIGN  i386

>Description:
When trying to force-umount a previously mounted USB mass-storage
filesystem after unplugging the device, the system locks up and reboots.

here, it happened with this device:
umass0: Sony Sony DSC, rev 1.00/2.10, addr 5
da0 at umass-sim0 bus 0 target 0 lun 0
da0: <Sony Sony DSC 2.10> Removable Direct Access SCSI-0 device
da0: 1.000MB/s transfers
da0: 123MB (253696 512 byte sectors: 64H 32S/T 123C)


>How-To-Repeat:
1) connect an USB mass-storage device
2) mount it like mount_msdosfs /dev/device /mnt/point
3) unplug the device (without umounting)
4) umount -f /mnt/point  <-- here, the system will freeze and reboot.



>Fix:
N/A
>Release-Note:
>Audit-Trail:
>Unformatted: