kern/43153: fss error branch error

[pooka%iki.fi@localhost]

>Number:         43153
>Category:       kern
>Synopsis:       fss error branch error
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 12 15:30:00 +0000 2010
>Originator:     Antti Kantee
>Release:        
>Organization:
>Environment:
>Description:
fss_create_snapshot() error branch might attempt to detach a disk
before one is attached.
>How-To-Repeat:
=== snip ===
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mount.h>

#include <dev/fssvar.h>

#include <fcntl.h>

int
main()
{
        struct fss_set fss;
        int fd;

        fd = open("/dev/rfss0", O_RDWR);
        memset(&fss, 0, sizeof(fss));
        ioctl(fd, FSSIOCSET, &fss);
}
=== snip ===

Tickling the kernel panic might also be possible with fssconfig, but it
does so many stats before making the system calls that dancing around
them takes more creativity than i have)
>Fix: