panic: devfs_populate_loop 343 stdin 0xfffff80001597000 0xdeadc0dedeadc0de

This happened while doing umount -A -t devfs, with /dev mounted and in
use, and another devfs mounted that should not have been used by
anything.

#0  doadump () at ../../../kern/kern_shutdown.c:233
#1  0x00000000c006a808 in db_fncall (dummy1=0, dummy2=0, dummy3=0, dummy4=0xfca34bd0 "") at ../../../ddb/db_command.c:488
#2  0x00000000c006a514 in db_command (last_cmdp=0xc0419268, cmd_table=0x0, aux_cmd_tablep=0xc03d1010,
    aux_cmd_tablep_end=0xc03d1028) at ../../../ddb/db_command.c:403
#3  0x00000000c006a638 in db_command_loop () at ../../../ddb/db_command.c:454
#4  0x00000000c006d238 in db_trap (type=-56406560, code=0) at ../../../ddb/db_main.c:221
#5  0x00000000c01901c8 in kdb_trap (type=107, code=0, tf=0xfca35060) at ../../../kern/subr_kdb.c:473
#6  0x00000000c02fea0c in trap (tf=0xfca35060) at ../../../sparc64/sparc64/trap.c:307
#7  0x00000000c0048fe0 in tl1_trap ()
#8  0x00000000c018fd9c in kdb_enter (msg=0xc03aa1c8 "panic") at ../../../kern/subr_kdb.c:267
#9  0x00000000c018fd9c in kdb_enter (msg=0xc03aa1c8 "panic") at ../../../kern/subr_kdb.c:267
#10 0x00000000c0170cec in panic (fmt=0xc03a0e00 "%s %d %s %p %p") at ../../../kern/kern_shutdown.c:539
#11 0x00000000c011d4d0 in devfs_populate_loop (dm=0xfffff800e5e04a00, cleanup=-1001106176)
    at ../../../fs/devfs/devfs_devs.c:341
#12 0x00000000c011d8c8 in devfs_cleanup (dm=0xfffff800e5e04a00) at ../../../fs/devfs/devfs_devs.c:456
#13 0x00000000c011e98c in devfs_unmount (mp=0xfffff8004b89d800, mntflags=134217728, td=0xfffff8000dea6e40)
    at ../../../fs/devfs/devfs_vfsops.c:124
#14 0x00000000c01d6e64 in dounmount (mp=0xfffff8004b89d800, flags=134217728, td=0xfffff8000dea6e40)
    at ../../../kern/vfs_mount.c:963
#15 0x00000000c01d6b9c in unmount (td=0xfffff8000dea6e40, uap=0xfca358c0) at ../../../kern/vfs_mount.c:895
#16 0x00000000c02ff124 in syscall (tf=0xfca35880) at ../../../sparc64/sparc64/trap.c:592
#17 0x00000000c0048dc0 in tl0_intr ()
#18 0x0000000000000000 in ?? ()
(kgdb)

Core is available (sparc64).

Kris