DF5141: softc=0xfffff8008dd19700 enq2=0xfffff800897a5000 (sz=128) dmat=0xfffff8008bbd64a0
DF5141: mlx_free #1 (mlx.c:453 path) ...
DF5141: mlx_free #1 returned (clean teardown, as designed)
DF5141: v1=0xfffff800897a5000 owns the freed block: YES
DF5141: mlx_free #2 (mlx_pci.c:204, the bug) ...
panic: memory chunk 0xfffff8008bbd64a0 is already free!
cpuid = 0
Trace beginning at frame 0xfffff80118523718
chunk_mark_free() at chunk_mark_free+0xae 0xffffffff80655dbe 
chunk_mark_free() at chunk_mark_free+0xae 0xffffffff80655dbe 
_kfree() at _kfree+0x262 0xffffffff806580e2 
bus_dma_tag_destroy() at bus_dma_tag_destroy+0x4b 0xffffffff80c1ac3b 
mlx_free() at mlx_free+0x11b 0xffffffff8056d30b 
df5141_modevent() at df5141_modevent+0x252 0xffffffff82600252 
Debugger("panic")

CPU0 stopping CPUs: 0x0000003e
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>