VOP_PRINT: 0xc775b128 interlock is locked but should not be

From -current as of yesterday.

----- console
ffs_snapshot: busy vnode: 0xc775b128: tag ufs, type VDIR, usecount 1, writecount 0, refcount 0, flags (VV_OBJBUF),
VOP_PRINT: 0xc775b128 interlock is locked but should not be
Debugger("Lock violation.
")
Stopped at      Debugger+0x55:  xchgl   %ebx,in_Debugger.0
db> trace
Debugger(c0739f8b,c073a861,c775b128,c0739f9c,ec1d3784) at Debugger+0x55
vfs_badlock(c0739f9c,c073a861,c775b128,ec1d3814,c058fdc2) at vfs_badlock+0x45
assert_vi_unlocked(c775b128,c073a861,c073a797,1,0) at assert_vi_unlocked+0x3a
vprint(c0749b7a,c775b128,c0749b5a,1a3,c3458200) at vprint+0x202
ffs_snapshot(c7720800,bfbfeef5,70,0,ec1d3ac0) at ffs_snapshot+0x13ce
ffs_mount(c7720800,cbfa5580,bfbfe994,ec1d3bec,cec05bd0) at ffs_mount+0x711
vfs_domount(cec05bd0,c94f0d10,cbfa5580,1010000,bfbfe994) at vfs_domount+0x884
mount(cec05bd0,ec1d3d14,c0753552,3ee,4) at mount+0xc0
syscall(2f,2f,2f,bfbfea04,bfbfeef3) at syscall+0x2c0
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (21, FreeBSD ELF32, mount), eip = 0x280bdf8f, esp = 0xbfbfe91c, ebp = 0xbfbfee1c ---
db> show locks
exclusive sleep mutex vnode interlock r = 0 (0xc775b128) locked _at_ ufs/ffs/ffs_snapshot.c:418
exclusive sleep mutex Giant r = 0 (0xc07aeaa0) locked _at_ kern/kern_physio.c:45
db> show lockedvnods
Locked vnodes
0xcc952de0: tag ufs, type VREG, usecount 1, writecount 0, refcount 16, lock type ufs: EXCL (count 1) by thread 0xcec05bd0 (pid:31496)
        ino 176, on dev ad0s1a (4, 12)
-----


-- 
Jun Kuriyama <kuriyama_at_imgsrc.co.jp> // IMG SRC, Inc.
             <kuriyama_at_FreeBSD.org> // FreeBSD Project