On Mon, Oct 08, 2007 at 05:31:46PM +1000, Geoff Wing wrote:
> On Monday 2007-10-08 09:04 +0200, Juergen Hannken-Illjes output:
> :> > (2007-10-08 05:00 UTC)
> :> > Some recent change is causing my system to crash with "savecore -c",
> :> > however during the OS coredump it's failing (and rebooting).
> :> > 
> :> > >From DDB, it gives something like:
> :> > 
> :> > uvm_fault  in  savecore:
> :> > 
> :> > specificdata_getspecific()  + 0x17
> :> > mount_getspecific()   + 0x26
> :> > fscow_run
> :> > spec_strategy
> :show buf <1. arg of fscow_run>
> :show vnode <vnode og this buf>
> 
> from a "boot -s" on my i386 (C2Duo w/ 2G mem)
> 
> (Hopefully I haven't fatfingered too much)
> 
> show buf cdde43e4
>   vp 0xcde44e70 lblkno 0xadc0 blkno 0xadc0 raw 560adc0 dev 0x01
>   error 0 flag 0x4020034 (ASYNC,BUSY,SCANNED,CACHE,VFLUSH)
>   bufsize 0x800 bcount 0x800 resid 0x0
>   data 0xccb6b800 saveaddr 0x0 dep 0x0 iodone 0x0
> 
> show vnode cde44e70
>  OBJECT 0xcde44e70 locked=0 pgops=0xc053246c npages=0 refs=2
>  VNODE flags 80<LOCKSWORK>
>  mp 0xc3240000 numoutput 1 size 0x81000000 writesize 0x81000000
>  data 0xcde435e0 usecount 2 writecount 1 holdcnt 5 numoutput 1
>  tag VT_UFS(1) type VBLK(3) mount 0xc324e000 typedate 0xc325fde0

Could you try this diff please:

Index: vfs_trans.c
===================================================================
RCS file: /cvsroot/src/sys/kern/vfs_trans.c,v
retrieving revision 1.13
diff -p -u -4 -r1.13 vfs_trans.c
--- vfs_trans.c	7 Oct 2007 14:48:38 -0000	1.13
+++ vfs_trans.c	8 Oct 2007 07:55:42 -0000
@@ -592,8 +592,10 @@ fscow_run(struct buf *bp)
 	if (bp->b_vp->v_type == VBLK)
 		mp = bp->b_vp->v_specmountpoint;
 	else
 		mp = bp->b_vp->v_mount;
+	if (mp == NULL)
+		return 0;
 
 	if ((cmi = mount_getspecific(mp, mount_cow_key)) == NULL)
 		return 0;
 

-- 
Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (Germany)