kern/41261: Crash with nullfs

[joerg%NetBSD.org@localhost]

>Number:         41261
>Category:       kern
>Synopsis:       Crash with nullfs
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 21 19:45:00 +0000 2009
>Originator:     Joerg Sonnenberger
>Release:        NetBSD 5.0rc4
>Organization:
TNF
>Environment:
>Description:
panic: kernel diagnostic assertion "success" failed: file "../../../../
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip ffffffff80518b75 cs 8 rflags 246 cr2  7f7ffd96cf00 cpl 
Stopped in pid 778.1 (mount_null) at    netbsd:breakpoint+0x5:  leave
db{3}> bt
breakpoint() at netbsd:breakpoint+0x5
cpu_Debugger() at netbsd:cpu_Debugger+0x9
panic() at netbsd:panic+0x24d
__kernassert() at netbsd:__kernassert+0x2d
uvm_pagealloc_strat() at netbsd:uvm_pagealloc_strat+0x549
pmap_growkernel() at netbsd:pmap_growkernel+0x322
uvm_map_prepare() at netbsd:uvm_map_prepare+0x230
uvm_map() at netbsd:uvm_map+0xd0
uvm_km_alloc() at netbsd:uvm_km_alloc+0xa8
kmem_backend_alloc() at netbsd:kmem_backend_alloc+0x76
vmem_xalloc() at netbsd:vmem_xalloc+0x3fc
vmem_alloc() at netbsd:vmem_alloc+0xf2
kmem_alloc() at netbsd:kmem_alloc+0x3d
hashinit() at netbsd:hashinit+0x56
nullfs_mount() at netbsd:nullfs_mount+0x176
VFS_MOUNT() at netbsd:VFS_MOUNT+0x44
do_sys_mount() at netbsd:do_sys_mount+0x625
sys___mount50() at netbsd:sys___mount50+0x33
syscall() at netbsd:syscall+0xb6

>How-To-Repeat:
Happens reproducable during bulk build setup.
>Fix: