Stopped at      kdb_alt_break_internal+0x17f:   movq    $0,kdb_why
db> set $lines 0
db> show mount
0xfffff80002a48b58 /dev/ada0p2 on / (ufs)

More info: show mount <addr>
db> show mount 0xfffff80002a48b58
0xfffff80002a48b58 /dev/ada0p2 on / (ufs)
    mnt_flag = SUJ, LOCAL, ROOTFS
    mnt_kern_flag = UNMOUNTF, SOFTDEP, NOINSMNTQ, EXTENDED_SHARED, NO_IOPF, NOASYNC, UNMOUNT, SUSPEND, LOOKUP_SHARED, 0x00002000
    mnt_opt = rw, fstype, fspath, from, errmsg
    mnt_stat = { version=537068824 type=53 flags=0x0000000100005000 bsize=4096 iosize=32768 blocks=4819671 bfree=3358899 bavail=2973326 files=2568190 ffree=2384479 syncwrites=4 asyncwrites=13929 syncreads=9618 asyncreads=748 namemax=255 owner=0 fsid=[1425918326, 88823482] }
    mnt_cred = { uid=0 ruid=0 }
    mnt_ref = 29470
    mnt_gen = 1
    mnt_nvnodelistsize = 29469
    mnt_activevnodelistsize = 16891
    mnt_writeopcount = 0
    mnt_maxsymlinklen = 120
    mnt_iosize_max = 131072
    mnt_hashseed = 942843318
    mnt_secondary_writes = 0
    mnt_secondary_accwrites = 352237
    mnt_gjprovider = NULL


List of active vnodes
vnode 0xfffff8002d0859c0: tag ufs, type VREG
    usecount 0, writecount 0, refcount 2 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80002ccc000 ref 0 pages 1 cleanbuf 0 dirtybuf 1
    lock type ufs: UNLOCKED
#0 0xffffffff808ec706 at __lockmgr_args+0xa16
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff80b4303e at ffs_sync+0x1fe
#6 0xffffffff809a8020 at sys_sync+0x110
#7 0xffffffff80ce5e1a at amd64_syscall+0x25a
#8 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 5, on dev ada0p2
vnode 0xfffff80029a5e9c0: tag ufs, type VDIR
    usecount 0, writecount 0, refcount 2 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80062732500 ref 0 pages 1 cleanbuf 0 dirtybuf 1
    lock type ufs: UNLOCKED
#0 0xffffffff808ecc7b at __lockmgr_args+0xf8b
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff8098ea13 at cache_lookup+0x553
#6 0xffffffff8098f88c at vfs_cache_lookup+0xac
#7 0xffffffff80dff47e at VOP_LOOKUP_APV+0xbe
#8 0xffffffff8099775c at lookup+0x5ac
#9 0xffffffff80996eb4 at namei+0x494
#10 0xffffffff809ab94e at kern_statat_vnhook+0xae
#11 0xffffffff809ab7dd at sys_stat+0x2d
#12 0xffffffff80ce5e1a at amd64_syscall+0x25a
#13 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 2167170, on dev ada0p2
vnode 0xfffff800625e6270: tag ufs, type VREG
    usecount 0, writecount 0, refcount 3 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80029bb2e00 ref 0 pages 10 cleanbuf 0 dirtybuf 2
    lock type ufs: UNLOCKED
#0 0xffffffff808ec706 at __lockmgr_args+0xa16
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff80b4303e at ffs_sync+0x1fe
#6 0xffffffff809a8020 at sys_sync+0x110
#7 0xffffffff80ce5e1a at amd64_syscall+0x25a
#8 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 2086660, on dev ada0p2
vnode 0xfffff8006276e750: tag ufs, type VREG
    usecount 0, writecount 0, refcount 3 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80029b9de00 ref 0 pages 10 cleanbuf 0 dirtybuf 2
    lock type ufs: UNLOCKED
#0 0xffffffff808ec706 at __lockmgr_args+0xa16
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff80b4303e at ffs_sync+0x1fe
#6 0xffffffff809a8020 at sys_sync+0x110
#7 0xffffffff80ce5e1a at amd64_syscall+0x25a
#8 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 2086658, on dev ada0p2
vnode 0xfffff8006279a750: tag ufs, type VREG
    usecount 0, writecount 0, refcount 2 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80062742a00 ref 0 pages 6 cleanbuf 0 dirtybuf 1
    lock type ufs: UNLOCKED
#0 0xffffffff808ec706 at __lockmgr_args+0xa16
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff80b4303e at ffs_sync+0x1fe
#6 0xffffffff809a8020 at sys_sync+0x110
#7 0xffffffff80ce5e1a at amd64_syscall+0x25a
#8 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 481613, on dev ada0p2
vnode 0xfffff80028089750: tag ufs, type VREG
    usecount 0, writecount 0, refcount 2 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff80062694800 ref 0 pages 2 cleanbuf 0 dirtybuf 1
    lock type ufs: UNLOCKED
#0 0xffffffff808ecc7b at __lockmgr_args+0xf8b
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0e2a at vn_close+0x10a
#4 0xffffffff809afb98 at vn_closefile+0x48
#5 0xffffffff808c83b9 at _fdrop+0x29
#6 0xffffffff808ca5b3 at closef+0x1d3
#7 0xffffffff808ca1fc at fdescfree+0x3cc
#8 0xffffffff808d5445 at exit1+0x3f5
#9 0xffffffff808d504e at sys_sys_exit+0xe
#10 0xffffffff80ce5e1a at amd64_syscall+0x25a
#11 0xffffffff80ccbddb at Xfast_syscall+0xfb
        ino 495678, on dev ada0p2
vnode 0xfffff8006279ac30: tag ufs, type VREG
    usecount 0, writecount 0, refcount 2 mountedhere 0
    flags (VI_ACTIVE)
    v_object 0xfffff8006272f900 ref 0 pages 7 cleanbuf 0 dirtybuf 1
    lock type ufs: UNLOCKED
#0 0xffffffff808ec706 at __lockmgr_args+0xa16
#1 0xffffffff80b444a4 at ffs_lock+0x84
#2 0xffffffff80e01c7b at VOP_LOCK1_APV+0xab
#3 0xffffffff809b0cb3 at _vn_lock+0x43
#4 0xffffffff809a0e1b at vget+0x5b
#5 0xffffffff80b4303e at ffs_sync+0x1fe