port-vax/46251: processes hang on iowait

[martin%NetBSD.org@localhost]

>Number:         46251
>Category:       port-vax
>Synopsis:       processes hang on iowait
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-vax-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Mar 23 12:35:00 +0000 2012
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.4
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD dead-to-the-world.duskware.de 6.99.4 NetBSD 6.99.4 (DEAD) #52: 
Thu Mar 22 23:15:11 CET 2012 
martin%night-porter.duskware.de@localhost:/usr/src/sys/arch/vax/compile/DEAD vax
Architecture: vax
Machine: vax
>Description:

Probably fallout from the gcc 4.5.1 and/or -O2 changes:

login in on the console of a vax station 4000 most of the time does not make
it to a command prompt, or hangs on first command that produces serious
amounts of output.

Kernel messages still make it out, only the process on the console hangs.
Sending a siginfo via ctrl-t says for example:

load: 0.03  cmd: stty 334 [iowait] 0.00u 0.00s 0% 0k

and the ps output says:

323 tty03 I    0:00.00 -tcsh 
331 tty03 Is   0:01.00 login 
334 tty03 Z+   0:00.00 (stty)

(why tty03?)

>How-To-Repeat:
s/a

>Fix:
n/a