if_rum dies on transmit...

[Lawrence Stewart]

Poul-Henning Kamp wrote:
> Has anybody else seen if_rum die when you try to transmit a file over
> a TCP connection ?
> 
> If I try to print across the network, upload a file with ftp or anything
> else of that general tenor, if_rum seems to hang the output queue and
> stops transmitting packets.

Yes I see the same thing with my D-LINK DWA-110 USB stick which shows up 
as a rum device. According to Sam who had a quick look at the issue for 
me when I first noticed it, the rum driver is in pretty bad shape and 
should be expected to be flaky.

I don't think the issue is specific to TCP connections though. I think 
it's related to timing of inbound/outbound packets. I would frequently 
trigger it when fetch ran as part of a port update, but it happened at 
other seemingly random times as well. I suspect that TCP incoming data 
and the outgoing ACKs might tickle the (locking? state machine?) bug 
more effectively than other traffic mixes.

> 
> Restarting wpa_supplicant mostly resolves the issue, but it does not
> on its own discover the problem.
> 
> According to tcpdump(8), packets are still received.
> 
> Any ideas ?
> 

I've never done any driver work so I have no idea how to resolve the 
issue, and just live with it randomly crapping out on me. I found 
restarting wpa_supplicant to be a hit and miss way to fix it. The 
easiest way to avoid panics or re occurrences was to pull the dongle, 
wait 5 secs, reinsert and then recreate the wlan dev and start 
wpa_supplicant.

Cheers,
Lawrence