Panicstring: command not in queue - with heavy scsi io

With -current built as of a few hours ago, I get Panicstring: command not
in queue with heavy scsi io.  I tried building in INVARIANT* off and that
didnt help.  Any hints of a workaround? or an earlyer date and time to
cvsyp to to not get it?

#0  doadump () at /usr/src/sys/kern/kern_shutdown.c:240
#1  0xc0332ac1 in boot (howto=260) at
/usr/src/sys/kern/kern_shutdown.c:372
#2  0xc0332f18 in panic () at /usr/src/sys/kern/kern_shutdown.c:550
#3  0xc04cc076 in trap_fatal (frame=0xe5aecc48, eva=0) at
/usr/src/sys/i386/i386/trap.c:818
#4  0xc04cb643 in trap (frame=
      {tf_fs = -965345256, tf_es = -441581552, tf_ds = -1070333936,
      tf_edi = 4, tf_esi = 16, tf_ebp = -441529188, tf_isp = -441529228,
      tf_ebx = 0, tf_edx = -1068300533, tf_ecx = -874986304, tf_eax = 16,
      tf_trapno = 12, tf_err = 0, tf_eip = -1070433397, tf_cs = 8,
      tf_eflags = 66199, tf_esp = 757588537, tf_ss = -1068824672}) at
      /usr/src/sys/i386/i386/trap.c:251
#5  0xc04b3098 in calltrap () at {standard input}:103
#6  0xc0327fd9 in _mtx_lock_sleep (m=0x10, opts=0, file=0x0, line=0) at
/usr/src/sys/kern/kern_mutex.c:635
#7  0xc031c845 in ithread_loop (arg=0xcb8e9900) at
/usr/src/sys/kern/kern_intr.c:533
#8  0xc031b491 in fork_exit (callout=0xc031c680 <ithread_loop>, arg=0x0,
frame=0x0) at /usr/src/sys/kern/kern_fork.c:796