kern/39186: crash during shutdown

[apb%cequrux.com@localhost]

>Number:         39186
>Category:       kern
>Synopsis:       crash during shutdown
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 21 20:25:00 +0000 2008
>Originator:     Alan Barrett
>Release:        NetBSD 4.99.69
>Organization:
Not much
>Environment:
System: NetBSD 4.99.69
Architecture: i386
Machine: i386
>Description:
    The system paniced during shutdown.

    I suspect that it had something to do with an external USB disk.

    The external disk (sd0) contained a disklabel, and partition sd0e
    was configured as a cgd device (cgd2).  The cgd2 device did not have
    a real disklabel.  The cgd2a partition (the entire disk, according
    to the fake disklabel) contained an ffs file system.  This file
    system was mounted on /mnt at the time of the shutdown.

>How-To-Repeat:
    [attach a USB disk drave as sd0]
    $ sudo cgdconfig cgd2 /dev/sd0e ${paramsfile}
    [enter the password]
    $ sudo mount /dev/sd2a /mnt
    [use the file system]
    $ sudo shutdown -r now
    [...]
    Done running shutdown hooks.
    Syncing disks... 10 3 done
    unmounting file systems...
    [...]
    unmounting / (/dev/wd0a)... done
    panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0)" failed 
file .../kern/kern_sync.c, line 189
    [...]
    db{0}> bt
    breakpoint ...
    panic ...
    __kernassert ...
    ltsleep ...
    usbd_transfer ...
    umass_setup_transfer ...
    umass_bbb_state ...
    usb_transfer_complete ...
    ehci_softintr ...
    softint_dispatch ...
    [...]
>Fix:
    Unknown