misc/109172: panic on double mounting the same mount point

[Alexander]

>Number:         109172
>Category:       misc
>Synopsis:       panic on double mounting the same mount point
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Feb 14 18:00:12 GMT 2007
>Closed-Date:
>Last-Modified:
>Originator:     Alexander
>Release:        FreeBSD 6.2
>Organization:
>Environment:
FreeBSD localhost 6.2-RELEASE FreeBSD 6.2-RELEASE #7: Thu Jan 25 21:09:24 MSK 2007     is at localhost:/usr/obj/usr/src/sys/LUKA  i386
>Description:
Sorry for my english!

I have double mounted the same mount point and then get panic.

/etc/fstab:
/dev/ad0s1		/mnt/c		ntfs	ro,noauto,-C=KOI8-R,-m=755,-u=luka,-g=luka	0	0

I`m working as user "is" (not the owner of the mount point).

is at localhost> mount /mnt/c
is at localhost> mount /mnt/c
panic...


>How-To-Repeat:
/etc/fstab:
/dev/ad0s1		/mnt/c		ntfs	ro,noauto,-C=KOI8-R,-m=755,-u=luka,-g=luka	0	0

is at localhost> mount /mnt/c
is at localhost> mount /mnt/c
panic...
>Fix:
Check if mount point has been mounted before mounting.
>Release-Note:
>Audit-Trail:
>Unformatted: