[NBLUG/talk] nasty messages from the kernel

[micxz at slashdomain]

Here's an excerpt from a posting to the NFS mailing list
from Neil Brown:
-------------Included message-----------------------
   Previously anonymous dentries were hashed (though with no name, the
   hash was pretty meaningless).  This meant that they would hang around
   after the last reference was dropped.  This was actually fairly
   pointless as they would never get referenced again, and caused a real
   problem as umount wouldn't discard them and so you got the message
                 printk("VFS: Busy inodes after unmount. "
                         "Self-destruct in 5 seconds.  Have a nice 
day...\n");

   In 2.4.6-pre3 I stopped hashing those dentries so now when the last
   reference is dropped, the dentry is freed.  So now there will never be
   more anonymous dentries than there are active nfsd threads.
---------------end included message-------------------

From:

http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg53163.html

--
Micxz

E Frank Ball wrote:
> nasty message from the kernel:  Self-destruct in 5 seconds.  Have a nice day...
> 
> I don't know if the nfs server is the cause of this problem or not.  The
> nfs server went down for a reboot, then I see the second line below:
> 
> May  9 06:39:53 napoleon kernel: nfs: server tank not responding, still trying
> 
> May  9 06:41:42 napoleon kernel: VFS: Busy inodes after unmount.  Self-destruct in 5 seconds.  Have a nice day...
> 
> May  9 06:49:36 napoleon kernel: nfs: server tank OK
> 
> 
> A while later the system hangs (see below).  Several other machines
> using the same NFS server recovered without any problems.  But it's not the
> first time napoleon has done this.  Any ideas how to prevent this?
> 
> 
> May 10 00:51:24 napoleon kernel: Unable to handle kernel paging request at virtual address 9f9079a5
> May 10 00:51:24 napoleon kernel:  printing eip:
> May 10 00:51:24 napoleon kernel: c016d757
> May 10 00:51:24 napoleon kernel: *pde = 00000000
> May 10 00:51:24 napoleon kernel: Oops: 0000
> May 10 00:51:24 napoleon kernel: parport_pc lp parport nfs nfsd lockd sunrpc iptable_filter ip_tables pcnet32 mii keybdev mousedev hid input usb-uhci usbcore ext3 jbd  
> May 10 00:51:24 napoleon kernel: CPU:    1
> May 10 00:51:24 napoleon kernel: EIP:    0060:[<c016d757>]    Not tainted
> May 10 00:51:24 napoleon kernel: EFLAGS: 00010286
> May 10 00:51:24 napoleon kernel: 
> May 10 00:51:24 napoleon kernel: EIP is at iput [kernel] 0x37 (2.4.20-28.9smp)
> May 10 00:51:24 napoleon kernel: eax: 9f90798d   ebx: c8bde300   ecx: c8bde310   edx: c0ac1d80
> May 10 00:51:24 napoleon kernel: esi: 9f90798d   edi: c9691800   ebp: 00007f98   esp: c1923f78
> May 10 00:51:24 napoleon kernel: ds: 0068   es: 0068   ss: 0068
> May 10 00:51:24 napoleon kernel: Process kswapd (pid: 7, stackpage=c1923000)
> May 10 00:51:24 napoleon kernel: Stack: 00000000 c016a510 d08eba37 c0ac1d98 c0ac1d80 c8bde300 c016aa1a c8bde300 
> May 10 00:51:24 napoleon kernel:        c8bde300 c1922000 00000000 000001d0 00000000 c016adb4 000086b9 c0147c8b 
> May 10 00:51:24 napoleon kernel:        00000006 000001d0 c1922000 c1922000 00000000 c1922401 00000000 c0147f53 
> May 10 00:51:24 napoleon kernel: Call Trace:   [<c016a510>] dput [kernel] 0x30 (0xc1923f7c))
> May 10 00:51:24 napoleon kernel: [<d08eba37>] nfs_dentry_iput [nfs] 0x57 (0xc1923f80))
> May 10 00:51:24 napoleon kernel: [<c016aa1a>] prune_dcache [kernel] 0x18a (0xc1923f90))
> May 10 00:51:24 napoleon kernel: [<c016adb4>] shrink_dcache_memory [kernel] 0x24 (0xc1923fac))
> May 10 00:51:24 napoleon kernel: [<c0147c8b>] do_try_to_free_pages_kswapd [kernel] 0x1b (0xc1923fb4))
> May 10 00:51:24 napoleon kernel: [<c0147f53>] kswapd [kernel] 0x83 (0xc1923fd4))
> May 10 00:51:24 napoleon kernel: [<c0147ed0>] kswapd [kernel] 0x0 (0xc1923fe4))
> May 10 00:51:24 napoleon kernel: [<c010759d>] kernel_thread_helper [kernel] 0x5 (0xc1923ff0))
> May 10 00:51:24 napoleon kernel: 
> May 10 00:51:24 napoleon kernel: 
> May 10 00:51:24 napoleon kernel: Code: 8b 46 18 85 c0 0f 85 b1 02 00 00 c7 44 24 04 40 6c 34 c0 8d 
> 
>