LOCKDEBUG kernel option crashes if vcpu > 1

[Emmanuel Dreyfus <manu%netbsd.org@localhost>]

Hi

An i386 domU kernel will crash on startup of LOCKDEBUG kernel option is
enabled and vcpu is more than 1.

The backtrace is below. Finding the offending code is easy, and I 
understand that LOCKDEBUG globals are not initialized at the time this
mutex is used. I am not sure of the proper fix, though.

panic: lockdebug_lookup: uninitialized lock (lock=0xc13754cc, from=c04147d1)
fatal breakpoint trap in supervisor mode                                    
trap type 1 code 0 eip c012f794 cs 9 eflags 286 cr2 0 ilevel 8 esp c0770c38
curlwp 0xc049e000 pid 0 lid 1 lowest kstack 0xc076f2c0                     
Stopped in pid 0.1 (system) at  netbsd:breakpoint+0x4:  popl    %ebp
breakpoint(c0484851,c04edfa0,c0484a54,c0770c64,0,c1207280,c13754cc,c13754cc,0,c049e000) at netbsd:breakpoint+0x4                                               
vpanic(c0484a54,c0770c64,c0770c88,c13754cc,0,c049e000,c0770ca8,c0359494,c0484a54,c13754cc) at netbsd:vpanic+0x117                                              
panic(c0484a54,c13754cc,c04147d1,c0358a20,c07d6000,6,c0770ca8,c0494090,c04147d1,6) at netbsd:panic+0x18                                                        
lockdebug_wantlock(c13754cc,c04147d1,0,c0412ff5,c049544c,c04de5a0,c0770ce8,c02381d1,c049544e,c04147a4) at netbsd:lockdebug_wantlock+0x194                      
mutex_enter(c13754cc,0,44fbf003,0,5e8,35e8,5e8,0,45983000,0) at netbsd:mutex_enter+0x314                                                                       
xen_kpm_sync(c04de5a0,6bd,44fbf003,0,3,0,0,c03593f5,c04e596c,c04f3664) at netbsd:xen_kpm_sync+0x141                                                            
pmap_growkernel(d811d000,d791d000,800000,c0770e94,c04f32e0,0,0,1,41727,c132c000)at netbsd:pmap_growkernel+0x39b
uvm_map_prepare(c04f3660,d791d000,800000,c04f32e0,0,0,1,41727,c0770ed4,1) at netbsd:uvm_map_prepare+0x1e9                                                      
uvm_map(c04f3660,c04f330c,800000,c04f32e0,0,0,1,41727,6666,6666) at netbsd:uvm_map+0x76                                                                        
ubc_init(c0475714,6,3,0,771000,c04f4348,1,c04e54e0,8000,0) at netbsd:ubc_init+0x198                                                                            
main(0,0,0,0,0,0,0,0,0,0) at netbsd:main+0x2b5


-- 
Emmanuel Dreyfus
manu%netbsd.org@localhost