softdep panic

I haven't seen this one reported, so this is just a datapoint. I was
running in X, no dump, no traceback: just the following left in the
message buffer after reboot:

panic: softdep_setup_inomapdep: found inode
KDB: enter: panic

Followed by a hundred or so instances of the following, with various
values for sp/fp:
Fatal trap 3: breakpoint instruction fault while in kernel mode
instruction pointer     = 0x8:0xc04b49b4
stack pointer           = 0x10:0xda60777c
frame pointer           = 0x10:0xda60777c
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, IOPL = 0
current process         = 23309 (vim)
trap number             = 3
panic: breakpoint instruction fault
KDB: enter: panic 

This was with a kernel from sources in or around the 11th/12th, and
its using vfs_subr 1.559, so predates the bug phk says was introduced
in 1.561.
This is a UP system with SCHED_ULE and PREEMPTION, with WITNESS disabled.