Hang when shutting down - seems umount and NFS related - kernel version 2.6.18.1

Hang when shutting down - seems umount and NFS related - kernel version 2.6.18.1

[Jesper Juhl]

I have a server that has the sole job of serving up a bunch of NFS
filesystems to webservers. The server is running kernel 2.6.18.1

A few days ago when attempting to reboot the server, the shutdown
process hung with a backtrace on the console. A photo was taken and is
available here:
  http://www.kernel.org/pub/linux/kernel/people/juhl/images/DSC00504.jpg

A quick (incomplete) text transcript of the photo is here:

EIP: [<c01a51a0>] nfs_clear_inode+0x61/0x6b SS:ESP 0068:eb476ee4
BUG: warning at kernel/exit.c:855/do_exit()
 do_exit			do_trap
 do_trap			do_invalid_op
 do_invalid_op			nfs_clear_inode
 scheduler_tick			radix_tree_gang_lookup_tag
 nfs_wait_on_reques_locked	error_code
 nfs3_forget_cached_acls	nfs_clear_inode
 clear_inode			dispose_list
 invalidate_inodes		generic_shutdown_super
 kill_anon_super		nfs_kill_super
 deactivate_super		sys_umount
 sys_readlink			syscall_call
BUG: umount/20593, lock held at task exit time!
  {alloc_super}
.. held by:  umount:20593
... acquired at:     generic_shutdown_super
/etc/rc6.d/S01reboot: line4: 20593 Segmentation fault      $*
                                                          [FAILED]
Unmounting filesystems (retry):

The problem has only manifested itself this once, so unfortunately not
reproducible on demand, but I hope that maybe someone more
knowledgable of NFS internals than me can figure out what went wrong
and a way to fix it in the future (if it's not already fixed) :-)

-- 
Jesper Juhl <jesper.juhl@gmail.com>
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Re: Hang when shutting down - seems umount and NFS related - kernel version 2.6.18.1

[Chuck Ebbert]

Jesper Juhl wrote:
> I have a server that has the sole job of serving up a bunch of NFS
> filesystems to webservers. The server is running kernel 2.6.18.1
> 
> A few days ago when attempting to reboot the server, the shutdown
> process hung with a backtrace on the console. A photo was taken and is
> available here:
>  http://www.kernel.org/pub/linux/kernel/people/juhl/images/DSC00504.jpg
> 
> A quick (incomplete) text transcript of the photo is here:
> 
> EIP: [<c01a51a0>] nfs_clear_inode+0x61/0x6b SS:ESP 0068:eb476ee4
> BUG: warning at kernel/exit.c:855/do_exit()

The real oops has scrolled off the screen.

Re: Hang when shutting down - seems umount and NFS related - kernel version 2.6.18.1

[Jesper Juhl]

On 27/02/07, Chuck Ebbert <cebbert@redhat.com> wrote:
> Jesper Juhl wrote:
> > I have a server that has the sole job of serving up a bunch of NFS
> > filesystems to webservers. The server is running kernel 2.6.18.1
> >
> > A few days ago when attempting to reboot the server, the shutdown
> > process hung with a backtrace on the console. A photo was taken and is
> > available here:
> >  http://www.kernel.org/pub/linux/kernel/people/juhl/images/DSC00504.jpg
> >
> > A quick (incomplete) text transcript of the photo is here:
> >
> > EIP: [<c01a51a0>] nfs_clear_inode+0x61/0x6b SS:ESP 0068:eb476ee4
> > BUG: warning at kernel/exit.c:855/do_exit()
>
> The real oops has scrolled off the screen.
>
I feared that might be the case, but still wanted to report the data I
had just in case something useful could be gleaned from it.
Ohh well, can't win 'em all...  Thanks for replying.

-- 
Jesper Juhl <jesper.juhl@gmail.com>
Don't top-post  http://www.catb.org/~esr/jargon/html/T/top-post.html
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