vn0: MBR magic not found; assume a COMPATIBILITY_SLICE (s0)
panic: ffs_isblock
cpuid = 5
Trace beginning at frame 0xfffff80117ba4268
ffs_isblock() at ffs_isblock+0x94 0xffffffff80910084 
ffs_isblock() at ffs_isblock+0x94 0xffffffff80910084 
ffs_alloccgblk.isra.1() at ffs_alloccgblk.isra.1+0x1be 0xffffffff809035be 
ffs_alloccg() at ffs_alloccg+0x2af 0xffffffff80903f0f 
ffs_hashalloc() at ffs_hashalloc+0x3c 0xffffffff8090231c 
ffs_alloc() at ffs_alloc+0x6f 0xffffffff8090406f 
Debugger("panic")

CPU5 stopping CPUs: 0x0000001f
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>