On Mon Jul 23 2007 at 19:33:41 +0200, Juergen Hannken-Illjes wrote:
> > simple_lock: uninitialized lock
> > lock: 0xce707ef8, currently at: ../../../../kern/kern_synch.c:184
> > uvm_fault(0xc05c3da0, 0xdeadb000, 1) -> 0xe
> > kernel: supervisor trap page fault, code=0
> > Stopped in pid 0.17 (system) at netbsd:strlen+0x8:    cmpb  $0,0(%eax)
> >  
> > strlen+0x8
> > vsnprintf+0x42
> > lock_printf(c0531a16,deadbeef,ffffbeef,b8,c) lock_printf+0x5f
> > _simple_lock+0x8c
> > ltsleep+0x18f
> > acquire_0xb0
> > _lockmgr+0x507
> > ufs_lock+0x4f
> > VOP_LOCK+0x25
> > vn_lock+0x9f
> > vrele+0x130
> > vget_0x90
> > ffs_sync_0xde
> > sync_fsync+0xaa
> > VOP_FSYNC+0x49 
> > sched_sync+0xf5
> > db> show lock  
> > Sorry, no record of a lock with address 0xc0492fd0 found.
> > db> sync
> > 
> > Mutex error: lockdebug_wantlock: locking against myself
> > ...
> > Turnstile chain at 0xc05e3960
> > => No active turnstile for this lock.
> > 
> > (I can only guess that the other box with a kernel built today is
> > freezing for similar reasons but I'm always in X when it happens.)
> 
> 
> I am able to reproduce this trap.
> 
> With rev. 1.289 of vfs_subr.c the lock type in function vclean()
> was changed from LK_DRAIN to LK_EXCLUSIVE.  This seems wrong.

Care to explain why you think it's wrong?  I had several theories on
why it could be wrong, but none of them held water.

> I managed to get this trace:
> 
> lwp_0	sys_munmap -> uvm_unmap_detach -> vrele ->
> 	    vn_lock -> VOP_LOCK -> ufs_lock -> SUCCESS
> 
> ioflush	sched_sync -> VOP_FSYNC -> sync_fsync -> ffs_sync -> vget ->
> 	    vn_lock -> VOP_LOCK -> ufs_lock -> EBUSY
> 	...
> 	    vrele -> vn_lock -> VOP_LOCK -> ufs_lock -> SLEEP

Is this the problematic thread?

> lwp_0	sys_munmap -> uvm_unmap_detach -> vrele ->
> 	    VOP_INACTIVE -> ufs_inactive -> VOP_UNLOCK -> ufs_unlock
> 	    VOP_INACTIVE -> ufs_inactive -> vrecycle -> vgonel -> vclean ->
> 		VOP_LOCK (*) -> ufs_lock -> SUCCESS
> 	    VOP_INACTIVE -> ufs_inactive -> vrecycle -> vgonel -> pool_put
> 
> (*) This is the lock that changed.
> -- 
> Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (Germany)

-- 
Antti Kantee <pooka@iki.fi>                     Of course he runs NetBSD
http://www.iki.fi/pooka/                          http://www.NetBSD.org/
    "la qualité la plus indispensable du cuisinier est l'exactitude"