ZFS and kernel panic (not kmem_map too small)

[John Doe]

Hi, All.

I'm running 7-CURRENT (cvsuped and builded at Fri May 11 12:27:49 EEST
2007) on Intel S3000AH motherboard, Xeon 3050 2.13GHz with 1GB RAM.
Using Areca ARC-1260 (16 port sata raid controller) with 16 400GB sata
drives in JBOD mode.

Create zpool with
# zpool create bfs radiz2 da0 da1 da2 da3 da4 da5 da6 da7 da8 da9 da10
da11 da12 da13 da14 da15

# zfs create bfs/test

# zfs list
NAME       USED  AVAIL  REFER  MOUNTPOINT
bfs        286M  4.97T  49.5K  /bfs
bfs/test   286M  4.97T   286M  /bfs/test

# zpool status -v
  pool: bfs
 state: ONLINE
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        bfs         ONLINE       0     0     0
          raidz2    ONLINE       0     0     0
            da0     ONLINE       0     0     0
            da1     ONLINE       0     0     0
            da2     ONLINE       0     0     0
            da3     ONLINE       0     0     0
            da4     ONLINE       0     0     0
            da5     ONLINE       0     0     0
            da6     ONLINE       0     0     0
            da7     ONLINE       0     0     0
            da8     ONLINE       0     0     0
            da9     ONLINE       0     0     0
            da10    ONLINE       0     0     0
            da11    ONLINE       0     0     0
            da12    ONLINE       0     0     0
            da13    ONLINE       0     0     0
            da14    ONLINE       0     0     0
            da15    ONLINE       0     0     0

errors: No known data errors

all seems fine, but i got kernel panic, while putting one file to zfs
filesystem using ftp:

lock order reversal:
 1st 0xffffff0031205938 zfs:&dr->dt.di.dr_mtx (zfs:&dr->dt.di.dr_mtx)
@ /usr/src/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/dbuf.c:1866
 2nd 0xffffff002f9ce418 zfs:&db->db_mtx (zfs:&db->db_mtx) @
/usr/src/sys/modules/zfs/../../contrib/opensolaris/uts/common/fs/zfs/dbuf.c:1837
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x3a
witness_checkorder() at witness_checkorder+0x4f9
_sx_xlock() at _sx_xlock+0x48
dbuf_sync_list() at dbuf_sync_list+0x7e
dbuf_sync_list() at dbuf_sync_list+0x114
dnode_sync() at dnode_sync+0x1ec
dmu_objset_sync() at dmu_objset_sync+0xec
dsl_pool_sync() at dsl_pool_sync+0x65
spa_sync() at spa_sync+0x309
txg_sync_thread() at txg_sync_thread+0x166
fork_exit() at fork_exit+0xaa
fork_trampoline() at fork_trampoline+0xe
--- trap 0, rip = 0, rsp = 0xffffffffaeeadd30, rbp = 0 ---
panic: Bad link elm 0xffffff003b362400 prev->next != elm
cpuid = 1
KDB: enter: panic

how can I provide more information to fix this problem?