Re: rpc_exit_task warning.

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Jul 26, 2012 at 12:43:46PM +0200, Taylan Develioglu wrote:
> I was wrong.
> 
> Changed kernel version to 2.6.39 and it's still happening.
> 
> Only other difference I can think of is the fact we now use lvm instead of a regular partition.

Did you change any of the clients at the same time you upgraded the
server?  (E.g. is it possible any of them are using NFSv4 now and
weren't before?)

--b.

> From: Taylan Develioglu 
> 
> Yes, but the previous server was using kernel version 2.6.39, so it looks like this is a regression.
...
> From: J. Bruce Fields [mailto:bfields@fieldses.org] 
> 
> 
> On Tue, Jul 24, 2012 at 08:58:43PM +0200, Taylan Develioglu wrote:
> > We just deployed a new nfs server and have about a hundred clients connected but are getting repeated kernel warnings on the server:
> 
> Did this replace an old server that didn't see these warnings?
> 
> > 
> > Clients and servers run 3.2.18 and 3.2.20 respectively. We do not use any security options.
> > 
> > I don't really have time to debug this, but I felt I should report it.
> > 
> > - Client
> >   ii  libevent-1.4-2                      1.4.13-stable-1
> >   ii  util-linux                          2.17.2-9
> >   ii  linux-image-3.2.0-0.bpo.2-amd64     3.2.18-1~bpo60+1
> >   ii  nfs-common                          1:1.2.2-4squeeze2
> > 
> > - Server
> >   ii  libevent-1.4-2                      1.4.13-stable-1
> >   ii  util-linux                          2.17.2-9
> >   ii  linux-image-3.2.0-0.bpo.2-amd64     3.2.20-1~bpo60+1
> >   ii  libnfsidmap2                        0.24-1~bpo60+1               
> >   ii  nfs-common                          1:1.2.5-4~bpo60+1            
> >   ii  nfs-kernel-server                   1:1.2.5-4~bpo60+1            
> > 
> > exportfs -v
> > /var/www/pictures
> >                 
> > x.x.x.x/22(rw,async,wdelay,root_squash,all_squash,no_subtree_check,ano
> > nuid=33,anongid=33)
> > /var/www/pictures
> >                 
> > 10.40.0.0/23(rw,async,wdelay,root_squash,all_squash,no_subtree_check,a
> > nonuid=33,anongid=33)
> > 
> > ----------------------------------------------------------------------
> > ------------------ [ 1913.662849] WARNING: at 
> > /build/buildd-linux_3.2.20-1~bpo60+1-amd64-tQMw4f/linux-3.2.20/net/sun
> > rpc/sched.c:630 rpc_exit_task+0x40/0x7a [sunrpc]()
> 
> That's a warning from rpc_task that both tk_action and RPC_TASK_KILLED were set on exit from rpc_calL_done.
> 
> Couldn't that happen if there's a race between rpc_killall and rpc_call_done trying to restart the task?  rpc_restart_call{_prepare} check RPC_TASK_KILLED before setting the action, but does anything prevent the flag being set after that check?
> 
> --b.
> 
> > [ 1913.662851] Hardware name: X8STi
> > [ 1913.662852] Modules linked in: nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc hmac drbd lru_cache cn ipmi_si ipmi_devintf ipmi_msghandler loop tpm_tis tpm parport_pc i2c_i801 i7core_edac i2c_core snd_pcm snd_timer snd ioatdma soundcore tpm_bios snd_page_alloc parport edac_core dca pcspkr psmouse processor serio_raw thermal_sys evdev joydev button ext4 mbcache jbd2 crc16 dm_mod sg sr_mod cdrom ses enclosure sd_mod crc_t10dif usb_storage usbhid hid uas uhci_hcd mptsas mptscsih mptbase scsi_transport_sas ahci libahci ehci_hcd libata usbcore aacraid usb_common scsi_mod e1000e [last unloaded: scsi_wait_scan]
> > [ 1913.662902] Pid: 11, comm: kworker/0:1 Tainted: G        W    3.2.0-0.bpo.2-amd64 #1
> > [ 1913.662904] Call Trace:
> > [ 1913.662909]  [<ffffffff810498ac>] ? warn_slowpath_common+0x78/0x8c 
> > [ 1913.662916]  [<ffffffffa0327871>] ? rpc_exit_task+0x40/0x7a 
> > [sunrpc] [ 1913.662922]  [<ffffffffa0327ddb>] ? 
> > __rpc_execute+0x71/0x23f [sunrpc] [ 1913.662928]  [<ffffffffa0327fe1>] 
> > ? rpc_execute+0x38/0x38 [sunrpc] [ 1913.662981]  [<ffffffff8105f96c>] 
> > ? process_one_work+0x1cc/0x2ea [ 1913.662985]  [<ffffffff8105fbb7>] ? 
> > worker_thread+0x12d/0x247 [ 1913.662987]  [<ffffffff8105fa8a>] ? 
> > process_one_work+0x2ea/0x2ea [ 1913.662990]  [<ffffffff8105fa8a>] ? 
> > process_one_work+0x2ea/0x2ea [ 1913.662993]  [<ffffffff810633c5>] ? 
> > kthread+0x7a/0x82 [ 1913.662998]  [<ffffffff8136ca74>] ? 
> > kernel_thread_helper+0x4/0x10 [ 1913.663000]  [<ffffffff8106334b>] ? 
> > kthread_worker_fn+0x147/0x147 [ 1913.663003]  [<ffffffff8136ca70>] ? 
> > gs_change+0x13/0x13 [ 1913.663005] ---[ end trace 7cee9f1fd80fe6ac 
> > ]---
> > ----------------------------------------------------------------------
> > ------------------
> > 
> > Regards,
> > 
> > Taylan
> > --
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