[CentOS] hung nfs mount

[Les Mikesell]

On Wed, Oct 16, 2013 at 7:05 AM, Patrick Begou
<Patrick.Begou at legi.grenoble-inp.fr> wrote:
> Did you also check /var/log/messages  on the nfs server side ?
>
> I had some NFS troubles with lockd some times ago and it was a firewall problem
> on the client:

No jumbo frames, no firewalling, no server side issues.  This is a lab
setup with on server holding home directories and about 10 other hosts
and VMs mounting it as /home.   There is heavy network testing on some
of the servers but the NFS connection runs over a different
interface/subnet.    I think the issue is triggered by a user running
NX/freenx sessions on multiple hosts and something gnome is trying to
lock in the common home directory, but regardless it is a kernel hang
to the point that I had to pull the plug to get the machine to shut
down.  And now one user (perhaps the only one with Gnome sessions on
multiple hosts) has things hanging again - even an ssh login by this
users hangs with this in the logs:

Oct 16 09:24:25 dev-l-01 kernel: INFO: task bash:20785 blocked for
more than 120 seconds.
Oct 16 09:24:25 dev-l-01 kernel: "echo 0 >
/proc/sys/kernel/hung_task_timeout_secs" disables this message.
Oct 16 09:24:25 dev--01 kernel: bash          D 0000000000000008     0
20785  20784 0x00000080
Oct 16 09:24:25 dev-l-01 kernel: ffff882066ecfba8 0000000000000082
0000000000000000 ffff881064998740
Oct 16 09:24:25 dev-l-01 kernel: ffff882066ecfb28 ffffffff8119b30a
ffff881065d12200 ffff881064998740
Oct 16 09:24:25 dev-l-01 kernel: ffff8820665ef058 ffff882066ecffd8
000000000000fb88 ffff8820665ef058
Oct 16 09:24:25 dev-l-01 kernel: Call Trace:
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff8119b30a>] ? dput+0x9a/0x150
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff8150f78e>]
__mutex_lock_slowpath+0x13e/0x180
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff8150f62b>] mutex_lock+0x2b/0x50
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff811907ab>] do_lookup+0x11b/0x230
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81190ff4>]
__link_path_walk+0x734/0x1030
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81143867>] ?
handle_pte_fault+0xf7/0xb50
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81191b7a>] path_walk+0x6a/0xe0
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81191d4b>] do_path_lookup+0x5b/0xa0
Oct 16 09:24:25 dev--l-01 kernel: [<ffffffff811929d7>] user_path_at+0x57/0xa0
Oct 16 09:24:25 dev--l-01 kernel: [<ffffffff81186d8c>] vfs_fstatat+0x3c/0x80
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81186efb>] vfs_stat+0x1b/0x20
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff81186f24>] sys_newstat+0x24/0x50
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff810dc937>] ?
audit_syscall_entry+0x1d7/0x200
Oct 16 09:24:25 dev--l-01 kernel: [<ffffffff810dc685>] ?
__audit_syscall_exit+0x265/0x290
Oct 16 09:24:25 dev-l-01 kernel: [<ffffffff8100b072>]
system_call_fastpath+0x16/0x1b

-- 
   Les Mikesell
      lesmikesell at gmail.com