mbuf strange behavior, panics using em driver

Barney Cordoba barney_cordoba at yahoo.com
Sun Apr 20 22:12:03 UTC 2008


I've encountered some regular panics in
bus_dmamap_load_mbuf_sg() and also complaints from the
ethernet code about packets without packet headers.
I've traced it to mbufs that are "freed" in filter
code. 

Strangely, I set up a test where I steal packets (as
if pfil grabbed the packet) and return NULL without
freeing the mbuf. Yet the mbufs continue to be used
over and over again (I'm monitoring the mbuf addresses
in ether_input()). Its as if the em driver is using
the mbuf continuously whether its been freed or not.

I also don't see mbuf cluster in use count going up as
I should with a forced memory leak. What is going on?

Barney


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