port-shark/49381: Shark 6.1 kernel hangs occasionally in vm_map

[is%netbsd.org@localhost]

>Number:         49381
>Category:       port-shark
>Synopsis:       Shark 6.1 kernel hangs occasionally in vm_map
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    port-shark-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 11 11:45:00 +0000 2014
>Originator:     Ignatios Souvatzis
>Release:        NetBSD 6.1.4_PATCH
>Organization:
>Environment:
	
	
System: NetBSD marie 6.1.4_PATCH NetBSD 6.1.4_PATCH (MARIE) #4: Sat Aug 23 20:25:06 CEST 2014 is@henrietta:/var/itch/sources/6.1/obj.shark/sys/arch/shark/compile/MARIE shark
(Userland still 5.1.3ish)
Architecture: arm
Machine: shark
>Description:

	Every about one to three weeks since I booted a 6.1 series
	kernel for evaluating upgrade to -6, my Shark's  hangs in
	vm_map. By which I mean: fork doesn't work anymore, exec*()
	doesn't work anymore.  This can not be worked around by
	killing processes using screen's kill window, so it doesn't
	look like a simple resource starvation of some sort.

	The machine can only be recovered from this state by rebooting
	it through ddb from the console or hardware reset.

>How-To-Repeat:
	Boot and wait, no specific trigger known.
>Fix:
	Downgrade to a 5.1.3 kernel.; the machine was rock stable 
	with the -5 kernel for several months at a time. 

>Unformatted: