panic: assertion "(((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0" failed in chunk_mark_free at /usr/src/sys/kern/kern_slaballoc.c:1675
chunk_mark_free() at chunk_mark_free+0x99 0xffffffff80655da9 
chunk_mark_free() at chunk_mark_free+0x99 0xffffffff80655da9 
slab_cleanup() at slab_cleanup+0xbb 0xffffffff8065662b 
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>