kern/49305: deadlocks on sparc64 SMP

[macallan%netbsd.org@localhost]

>Number:         49305
>Category:       kern
>Synopsis:       deadlocks on sparc64 SMP
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Oct 22 09:50:00 +0000 2014
>Originator:     Michael Lorenz
>Release:        6.99.45 and newer
>Organization:
>Environment:
NetBSD blackbush 7.99.1 NetBSD 7.99.1 (BLACKBUSH) #1: Sun Oct 19 11:11:01 EDT 2014  root@blackbush:/stuff/build/obj_sparc64/sys/arch/sparc64/compile/BLACKBUSH sparc64
/
>Description:
Under load my Sun Blade 2500 will sooner or later deadlock.
I tracked this down to one specific commit - net/pktqueue.c -r1.7. A -current kernel with just this reversed is stable.
I have not seen any deadlocks on non-SMP hardware or on slower machines, like my Ultra 60.
>How-To-Repeat:
build.sh -j4 distribution with sources over nfs. Usually deadlocks within an hour, may take significantly longer.
>Fix:
downgrade net/pktqueue.c to -r1.6