On Tue, Aug 01, 2017 at 02:23:42PM +0100, Laurence Tratt wrote:
> >Synopsis:
> iwm: could not add MAC context
> >Category:
> kernel
> >Environment:
> System : OpenBSD 6.1
> Details : OpenBSD 6.1-current (GENERIC.MP) #30: Mon Jul 31 22:48:24
> MDT 2017
>
> [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
>
> Architecture: OpenBSD.amd64
> Machine : amd64
> >Description:
> On the Jul 31st snapshot, iwm panics with heavy traffic on a WPA2
> enterprise
> network. So far I haven't seen this on a non-WPA2 network. Screenshot of
> the
> panic:
>
> https://imagebin.ca/v/3VNEJhDM7fas
>
> In case it's useful (though I guess it isn't), here's the trace for the
> other
> CPUs:
>
> https://imagebin.ca/v/3VNEqn6y9s6N
This is a driver bug. It looks like a race between code which resets
the device and code which acts upon frames received from the AP.
A proper fix is still in progress, but for now this is the best
fix/workaround I can offer:
Index: if_iwm.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_iwm.c,v
retrieving revision 1.204
diff -u -p -r1.204 if_iwm.c
--- if_iwm.c 23 Jul 2017 13:51:11 -0000 1.204
+++ if_iwm.c 2 Aug 2017 18:05:56 -0000
@@ -5869,6 +5869,12 @@ iwm_newstate_task(void *psc)
return;
}
+ /* XXX Avoid invalid transition due to race conditions. */
+ if (ostate == IEEE80211_S_INIT && nstate > IEEE80211_S_SCAN) {
+ splx(s);
+ return;
+ }
+
if (ostate == IEEE80211_S_SCAN)
iwm_led_blink_stop(sc);
