kern/53827: File system lockup

[martin%NetBSD.org@localhost]

>Number:         53827
>Category:       kern
>Synopsis:       File system lockup
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 02 10:45:00 +0000 2019
>Originator:     Martin Husemann
>Release:        NetBSD 8.99.30
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD whoever-brings-the-night.aprisoft.de 8.99.30 NetBSD 8.99.30 (WHOEVER) #244: Tue Jan 1 20:33:47 CET 2019 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/sparc64/compile/WHOEVER sparc64
Architecture: sparc64
Machine: sparc64
>Description:

Running tests with latest current locked up my machine:

kernel/t_umountstress (91/764): 2 test cases
    fileop: [0.994189s] Passed.
    mountlist: 

No more output on that session, but console was still responsive.
I could not log in though, the login process hangs after logging the log in
to syslog.

>How-To-Repeat:
s/a

>Fix:
n/a