ath(4) panic: bus_dmamap_load_sg: no mbuf packet header!

[Sam Leffler]

Pawel Jakub Dawidek wrote:
> Hi.
> 
> I configured NAT (using pf(4)) on my laptop:
> 
> MacOSX (Tiger) <-----> ath0[my laptop]bge0 <-----> local machine
> 
> When I started downloading few files on Mac from "local machine" via FTP
> in parallel I got this panic after few minutes (I was able to reproduce it):
> 
> panic: bus_dmamap_load_sg: no mbuf packet header!
> 
> And the backtrace:
> 
> panic()
> bus_dmamap_load_sg()+0x2a
> ath_start()+0x2ae
> taskqueue_run()+0xaf
> taskqueue_swi_run()+0x13
> ithread_loop()
> ...
> 
> Any ideas?
> 

I'm guessing you hand-transcribed stuff since there are typos (e.g. 
bus_dmamap_load_mbuf_sg is not called from ath_start but is called from 
ath_tx_start which is called from ath_start).  This indicates the mbuf 
chain is malformed (missing a packet header).  Since the packet is 
apparently coming in via pf you might want to look there.

	Sam