Deadlock between background fsck and cvsup, both stuck in snaplk

Hi,

I recently reinstalled my scratch box, last time I turned it off, I
didn't shut it down nicely so when I booted it today the file systems
needed a fsck.

While bgfsck was still running I started a cvsup to update /usr/ports/,
which ran fine for a while, and then stopped, and now both cvsup and
fsck are waiting for snaplk

The box is running 5.1-CURRENT as of June 8th

When it booted it logged this

...
da0 at ahc0 bus 0 target 0 lun 0
da0: <IBM DCAS-34330 S65A> Fixed Direct Access SCSI-2 device 
da0: 20.000MB/s transfers (20.000MHz, offset 15)
da0: 4134MB (8467200 512 byte sectors: 255H 63S/T 527C)
da1 at ahc1 bus 0 target 0 lun 0
da1: <IBM DORS-32160W WA6A> Fixed Direct Access SCSI-2 device 
da1: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing Enabled
da1: 2063MB (4226725 512 byte sectors: 255H 63S/T 263C)
Mounting root from ufs:/dev/da0s1a
WARNING: / was not properly dismounted
/: mount pending error: blocks 4 files 0
WARNING: /usr was not properly dismounted
/usr: superblock summary recomputed
WARNING: /usr/obj was not properly dismounted
WARNING: /var was not properly dismounted
acquiring duplicate lock of same type: "vnode interlock"
 1st vnode interlock _at_ /usr/src/sys/ufs/ffs/ffs_snapshot.c:477
 2nd vnode interlock _at_ /usr/src/sys/ufs/ffs/ffs_snapshot.c:480
Stack backtrace:

But the backtrace isn't in the output of dmesg nor in /var/log/messages

The processes currently waiting for snaplk are

olive# ps auxl | grep snaplk
root      41  0.0  0.0     0   12  ??  DL    8:47PM   0:01.44  (syncer)            0     0   0  -4  0 snaplk
root     496  0.0  1.5  2280 1848  ??  DN    8:49PM   0:08.78 fsck_ufs -p -B /     0   481   0  -4  4 snaplk
root     537  0.0  4.2  6192 5280  p0  D     8:53PM   0:34.17 /usr/local/bin/c     0     1   0  -4  0 snaplk
root     590  0.0  0.1   328  180  p0  R+    9:08PM   0:00.01 grep snaplk          0   520   0 108  0 -     

Any ideas ?

/Jesper

-- 
Jesper Skriver, jesper(at)skriver(dot)dk  -  CCIE #5456

One Unix to rule them all, One Resolver to find them,
One IP to bring them all and in the zone to bind them.