amd64/180894: rm -rf causes kernel panic

[David Noel]

>Number:         180894
>Category:       amd64
>Synopsis:       rm -rf causes kernel panic
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sat Jul 27 19:10:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     David Noel
>Release:        9.0
>Organization:
>Environment:
9.0-RELEASE
>Description:
rm -rf on a directory causes kernel panic and reboot.

panic: ufs_dirrem: Bad link count 2 on parent
cpuid = 0
KDB: stack backtrace:
#0 0xffffffff808680fe at kdb_backtrace+0x5e
#1 0xffffffff80832cb7 at panic+0x187
#2 0xffffffff80a700e3 at ufs_rmdir+0x1c3
#3 0xffffffff80b7d484 at VOP_RMDIR_APV+0x34
#4 0xffffffff808ca32a at kern_rmdirat+0x21a
#5 0xffffffff80b17cf0 at amd64_syscall+0x450
#6 0xffffffff80b03427 at Xfast_syscall+0xf7

I repeated this several times to be certain and it consistently blew up in my face so I'm guessing it's behaving as designed. It seems like there should be a better way to handle this than a kernel panic though. I've never crashed a box with "rm -rf" before. Might there be some alternative than the current design?
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: