Re: kern/59450: bwfm0 network interface stops responding (No buffer space available) on large downloads

[Ramiro Aceves <ea1abz%gmail.com@localhost>]

El 31/5/25 a las 2:35, camthesaxman%gmail.com@localhost escribió:
> > Number:         59450
> > Category:       kern
> > Synopsis:       bwfm0 network interface stops responding (No buffer space available) on large downloads
> > Confidential:   no
> > Severity:       critical
> > Priority:       medium
> > Responsible:    kern-bug-people
> > State:          open
> > Class:          sw-bug
> > Submitter-Id:   net
> > Arrival-Date:   Sat May 31 00:35:00 +0000 2025
> > Originator:     Cameron
> > Release:        10.1
> > Organization:
> none
> > Environment:
> NetBSD raspberrypi 10.1_STABLE NetBSD 10.1_STABLE (GENERIC) #0: Fri May 16 05:17:34 UTC 2025  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/evbarm/compile/GENERIC evbarm
> > Description:
> When trying to download large files (>12 MB), the Raspberry Pi 3 onboard WiFi module will stop functioning with a (No buffer space available) error, and the entire system must be restarted. I don't know if this is a problem with the driver, something in the TCP/IP stack, or some other problem, so feel free to change the category as appropriate.
> > How-To-Repeat:
> Install NetBSD on a Raspberry Pi 3 as described here: https://wiki.netbsd.org/ports/evbarm/raspberry_pi/#index7h2
> I used armv7.img.gz and decompressed it onto an SD card.
> Configure networking with the onboard WiFi adapter as outlined here: https://www.netbsd.org/docs/guide/en/chap-net-practice.html#chap-net-practice-lan-setup-wlan
> The interface name should be bwfm0. Do a `ping www.google.com` test to confirm that it's working.
> Setup pkgin as described here: https://www.netbsd.org/docs/guide/en/chap-boot.html#chap-boot-pkgsrc (I added the PKG_PATH variable to /etc/profile so that it persists across reboots)
> Attempt to install a reasonably large package (for example: `pkgin install neverball`)
> After a while, the download will stall completely (for me, it seems to hang after downloading 12 MB of neverball-1.6.0nb16.tar.gz every time)
> The following messages will be repeatedly *spammed* to the console and will continue for several minutes after Ctrl+C is pressed:
>
> May 30 19:15:29 raspberrypi mDNSResponder: mDNSPlatformSendUDP got error 55 (No buffer space available) sending packet to 224.0.0.251 on interface 192.168.0.163/bwfm0/3
> May 30 19:15:29 raspberrypi mDNSResponder: mDNSPlatformSendUDP got error 55 (No buffer space available) sending packet to FF02:0000:0000:0000:0000:0000:0000:00FB on interface 192.168.0.163/bwfm0/3
> May 30 19:15:29 raspberrypi dhcp[569]: ps_root_recvmsg: No buffer space available
>
> At this point the network interface is in an unusable state and will no longer function. Not even doing `ifconfig bwfm0 down; ifconfig bwfm0 up` will restore it. The only way to get it working again is to reboot.
>
> This can also be reproduced by trying to download a very large file, for example: `curl http://xcal1.vodafone.co.uk/1GB.zip > /dev/null`
> > Fix:

Hello

I have been suffering for months the same bwfm driver network problem 
that leave my raspberrypiZero frequently unreachable by ssh. As an 
emergency fix I have a script that reboots the piZero when network is 
lost. It is a very odd fix but at least I do not have to reboot it 
physically. It is a bit sad cause NetBSD works very well in the piZero 
but this problem removes a big percent of that little evb computer 
usefullness. Network link is very sensitive to signal strenght, router 
channel change and so on. Now I have a TP-LINK repeater that I 
configured as an access point that is at 1.5 meter distance of the 
rpiZero. Uptime is better now and I can transfer big files. But 
sometimes it stucks....

An improvement will be greatly welcome. If you someone tests I can 
colaborate.

Regards.
Ramiro.