panic: vfs_getopt: caller passed 'opts' as NULL

[Ulrich Spoerlein]

RELENG_6 from 30th October, trying to do two nullfs mounts from two
amd-mounted directories (i.e., NFS mounts).

Funny thing is, this amd/nfs/mount_nullfs is working on several other
machines from a RELENG_6 checkout of 25th October.

panic: vfs_getopt: caller passed 'opts' as NULL
cpuid = 1
KDB: stack backtrace:
kdb_backtrace(100,c8506780,c852c870,c8df3450,e8d0ca5c,...) at kdb_backtrace+0x29
panic(c089c395,c852c870,c8721b90,e8d0ca80,e8d0cadc,...) at panic+0x114
vfs_getopt(0,c8df3450,e8d0ca58,e8d0ca5c,0,...) at vfs_getopt+0x1d
nullfs_mount(c8721b90,c8506780,0,c8df46c0,c8cd1c3c,...) at nullfs_mount+0x70
vfs_domount(c8506780,c852c870,c8433a40,0,c851cc50,c0971700,0,c089be7a,2a3)
at vfs_domount+0x687
vfs_donmount(c8506780,0,c86ffd00,c86ffd00,0,...) at vfs_donmount+0x2ef
nmount(c8506780,e8d0cd04) at nmount+0x8b
syscall(3b,3b,3b,bfbfe3b4,bfbfec0c,...) at syscall+0x25b
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (378, FreeBSD ELF32, nmount), eip = 0x280ba4d7, esp =
0xbfbfe33c, ebp = 0xbfbfebb8 ---
KDB: enter: panic
[thread pid 60225 tid 100085 ]
Stopped at      kdb_enter+0x2b: nop