kern/43917: panic: cnopen: no console device

[Patrick Welche <prlw1%inf.phy.cam.ac.uk@localhost>]

>Number:         43917
>Category:       kern
>Synopsis:       panic: cnopen: no console device
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Sep 27 17:00:00 +0000 2010
>Originator:     Patrick Welche
>Release:        NetBSD 5.99.37
>Organization:
        
>Environment:
NetBSD 5.99.37/amd64
cpu0 at mainbus0 apid 0: AMD 686-class, 2712MHz, id 0x60fb2
cpu0: AMD PowerNow! Technology 2700 MHz
cpu0: available frequencies (MHz): 1000 1800 2000 2200 2400 2600 2700
cpu1 at mainbus0 apid 1: AMD 686-class, 2712MHz, id 0x60fb2
ioapic0 at mainbus0 apid 4: pa 0xfec00000, version 11, 24 pins
acpi0 at mainbus0: Intel ACPICA 20100528
acpi0: X/RSDT: OemId <Nvidia,ASUSACPI,42302e31>, AslId <AWRD,00000000>
acpi0: SCI interrupting at int 9

>Description:
When trying to boot an amd64 kernel with

options         CONSDEVNAME="\"com\"",CONADDR=0x3f8,CONSPEED=115200
options         CONS_OVERRIDE   # Always use above! independent of boot info
options         POWERNOW_K8

among other things, and no acpicpu, booting fails with
...
boot device: raid0
root on raid0a dumps on raid0b
root file system type: ffs
panic: cnopen: no console device
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff801eaaa5 cs 8 rflags 246 cr2  7f7ffd30f948 cpl 0 
rsp ffff80004e1f97b0
Stopped in pid 2.1 (init) at    netbsd:breakpoint+0x5:  leave
db{0}> bt
breakpoint() at netbsd:breakpoint+0x5
panic() at netbsd:panic+0x2ba
cnopen() at netbsd:cnopen+0xf1
cdev_open() at netbsd:cdev_open+0x63
spec_open() at netbsd:spec_open+0x167
VOP_OPEN() at netbsd:VOP_OPEN+0x62
vn_open() at netbsd:vn_open+0x1fc
sys_open() at netbsd:sys_open+0xd7
syscall() at netbsd:syscall+0x92

Bisecting, a kernel built from source with tag

  D2010.07.27.04.00.00

boots successfully, but one built from

  D2010.07.27.08.00.00

and following fails with the above panic.

Index: sys/dev/acpi/acpi_cpu.h
Index: sys/dev/acpi/acpi_cpu_cstate.c
Index: sys/dev/acpi/acpi_quirks.c
Index: sys/dev/isa/aria.c
Index: sys/dev/pci/piixpm.c
Index: sys/ufs/ext2fs/ext2fs_vfsops.c

are the only files which changed in that window. (NB the kernel doesn't
have acpicpu enabled.)
>How-To-Repeat:
        
>Fix: