softupdate with journal panic

[Buganini]

I just bumped into this problem again during port upgrading.

Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0x30
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff808a5a5c
stack pointer           = 0x28:0xffffff8121bfb4e0
frame pointer           = 0x28:0xffffff8121bfb500
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 63342 (conftest)
trap number             = 12
panic: page fault
cpuid = 1
Uptime: 9m13s
Physical memory: 4012 MB


#0  doadump () at pcpu.h:224
#1  0xffffffff80643fd0 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:418
#2  0xffffffff806443f3 in panic (fmt=0x0)
    at /usr/src/sys/kern/kern_shutdown.c:591
#3  0xffffffff8097352d in trap_fatal (frame=0xfffffe0134e47000,
eva=Variable "eva" is not available.
)
    at /usr/src/sys/amd64/amd64/trap.c:833
#4  0xffffffff809738f1 in trap_pfault (frame=0xffffff8121bfb430, usermode=0)
    at /usr/src/sys/amd64/amd64/trap.c:749
#5  0xffffffff80973cef in trap (frame=0xffffff8121bfb430)
    at /usr/src/sys/amd64/amd64/trap.c:501
#6  0xffffffff8095e854 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:228
#7  0xffffffff808a5a5c in free_jremref (jremref=0x0)
    at /usr/src/sys/ufs/ffs/ffs_softdep.c:3576
#8  0xffffffff808afdb2 in cancel_diradd (dap=0xfffffe012fb91880,
    dirrem=0xfffffe012fa65d00, jremref=0x0, dotremref=0xfffffe0130040a80,
    dotdotremref=0x0) at /usr/src/sys/ufs/ffs/ffs_softdep.c:6783
#9  0xffffffff808b0050 in newdirrem (bp=0xffffff80f253bc20,
    dp=0xfffffe001418b1f8, ip=0xfffffe012880a3f0, isrmdir=1,
    prevdirremp=0xffffff8121bfb630) at /usr/src/sys/ufs/ffs/ffs_softdep.c:7206
#10 0xffffffff808b050a in softdep_setup_directory_change (
    bp=0xffffff80f253bc20, dp=0xfffffe001418b1f8, ip=0xfffffe012880a3f0,
    newinum=9114624, isrmdir=1) at /usr/src/sys/ufs/ffs/ffs_softdep.c:7272
#11 0xffffffff808c28e6 in ufs_dirrewrite (dp=0xfffffe001418b1f8,
    oip=0xfffffe012880a3f0, newinum=9114624, newtype=4, isrmdir=1)
    at /usr/src/sys/ufs/ufs/ufs_lookup.c:1304