kern/39924: kernel can't deal with mounting root on ffs with unknown wapbl type

[reinoud%NetBSD.org@localhost]

>Number:         39924
>Category:       kern
>Synopsis:       kernel can't deal with mounting root on ffs with unknown wapbl 
>type
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Nov 15 11:35:00 +0000 2008
>Originator:     Reinoud Zandijk
>Release:        NetBSD 5.99.02
>Organization:
NetBSD
        
>Environment:
        
        
System: NetBSD heethoofdje.13thmonkey.org 5.99.02 NetBSD 4.99.02 (GENERIC) 
Architecture: i386
Machine: i386
>Description:
When something goes wrong in wapbl, the wapbl type can be set to garbage. 
How that happends is not known, but happends here on an endless loop crash.

Most common values of the unrecognized wapbl types is 0x000241ed or similar 
sized values.

On reboot the kernel complains about the unrecognized wapbl type and 
replies: 
no file system for wd0 (dev 0x0)
cannot mount root, error = 79

further tries to mount a root are in vain and you're stuck with a non 
booting kernel.

        
>How-To-Repeat:
Generate activity like building a package or deleting a source tree and 
press reset button when the machine seems to freeze. (i'll file a PR about 
this later)

        
>Fix:
hard... a 4.0 kernel without WAPBL will fsck and mount the FS fine but 
won't reset the wapbl type. Using `chroot' on the device and then call the 
5.0's `tunefs -l0 /dev/rwd0a' doesn't allways work... it leaves the bad 
wapbl type.

What could help is booting a 5.0 kernel without wapbl support to disable it 
correctly with the tunefs ?

        

>Unformatted: