kern/185425: iwn difficulties in busy radio environments

[Nathan Whitehorn]

>Number:         185425
>Category:       kern
>Synopsis:       iwn difficulties in busy radio environments
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jan 02 21:00:00 UTC 2014
>Closed-Date:
>Last-Modified:
>Originator:     Nathan Whitehorn
>Release:        11-CURRENT
>Organization:
>Environment:
FreeBSD wanderer.tachypleus.net 11.0-CURRENT FreeBSD 11.0-CURRENT #41 r260039M: Sun Dec 29 13:22:33 EST 2013     root at wanderer.tachypleus.net:/usr/obj/usr/src/sys/WANDERER  amd64
>Description:
In busy radio environments (i.e. not at home), using wpa_supplicant reliably causes NIC crashes involving printing errors about "NMI_FIRMWARE_WATCHDOG" to the console. Resetting the interface (an up/down cycle) restores its operation for a time.

This problem seems specific to wpa_supplicant. If I am connected to an open network and wpa_supplicant is running, the NIC will crash. If I turn wpa_supplicant off and just connect with ifconfig ssid foo, it will not crash. I suspect it is a scanning-related race.

The card in question is:
iwn0 at pci0:3:0:0:        class=0x028000 card=0x11108086 chip=0x42308086 rev=0x61 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'PRO/Wireless 4965 AG or AGN [Kedron] Network Connection'
>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: