login: unmount(/mnt/nfsx): forced umount of "(null)" - 2 namecache refs, 2 mount refs
unmount(/mnt/nfsx): (0xfffff8008eddbc00): 2 namecache refs, 2 mount refs still present
unmount(/mnt/nfsx): forced umount of "(null)" - 1 namecache refs, 1 mount refs
unmount(/mnt/nfsx): (0xfffff8008eddb800): 1 namecache refs, 1 mount refs still present
unmount(/mnt/nfsx): forcing unmount

vflush: Warning, cannot destroy busy device vnode
NFS inodes: slab 0xfffff80118720000 1 objects were still allocated
malloc_uninit: 576 bytes of 'NFS inodes' still allocated on cpu 6
panic: unmount: dangling vnode
cpuid = 2
Trace beginning at frame 0xfffff801186677b8
dounmount() at dounmount+0x87c 0xffffffff80701bfc 
dounmount() at dounmount+0x87c 0xffffffff80701bfc 
sys_unmount() at sys_unmount+0x1f2 0xffffffff80701e02 
syscall2() at syscall2+0x11e 0xffffffff80bd6a0e 
Debugger("panic")

CPU2 stopping CPUs: 0x0000003b
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)