On 10/28/2024 5:18 AM, Benoît Gschwind wrote:
Hello,
The issue trigger again, I attached the result of:
# dmesg -W | tee dmesg.txt
using:
# echo t > /proc/sysrq-trigger
I have the following PID stuck:
1474 D (disk sleep) 0:54:58.602 [nfsd]
1475 D (disk sleep) 0:54:58.602 [nfsd]
1484 D (disk sleep) 0:54:58.602 [nfsd]
1495 D (disk sleep) 0:54:58.602 [nfsd]
Hmm, 1495 is stuck in nfsd4_create_session
> [427468.304955] task:nfsd state:D stack:0 pid:1495
ppid:2 flags:0x00004000
> [427468.304962] Call Trace:
> [427468.304965] <TASK>
> [427468.304971] __schedule+0x34d/0x9e0
> [427468.304983] schedule+0x5a/0xd0
> [427468.304991] schedule_timeout+0x118/0x150
> [427468.305003] wait_for_completion+0x86/0x160
> [427468.305015] __flush_workqueue+0x152/0x420
> [427468.305031] nfsd4_create_session+0x79f/0xba0 [nfsd]
> [427468.305092] nfsd4_proc_compound+0x34c/0x660 [nfsd]
> [427468.305147] nfsd_dispatch+0x1a1/0x2b0 [nfsd]
> [427468.305199] svc_process_common+0x295/0x610 [sunrpc]
> [427468.305269] ? svc_recv+0x491/0x810 [sunrpc]
> [427468.305337] ? nfsd_svc+0x370/0x370 [nfsd]
> [427468.305389] ? nfsd_shutdown_threads+0x90/0x90 [nfsd]
> [427468.305437] svc_process+0xad/0x100 [sunrpc]
> [427468.305505] nfsd+0x99/0x140 [nfsd]
> [427468.305555] kthread+0xda/0x100
> [427468.305562] ? kthread_complete_and_exit+0x20/0x20
> [427468.305572] ret_from_fork+0x22/0x30
and the other three are stuck in nfsd4_destroy_session
> [427468.298315] task:nfsd state:D stack:0 pid:1474
ppid:2 flags:0x00004000
> [427468.298322] Call Trace:
> [427468.298326] <TASK>
> [427468.298332] __schedule+0x34d/0x9e0
> [427468.298343] schedule+0x5a/0xd0
> [427468.298350] schedule_timeout+0x118/0x150
> [427468.298362] wait_for_completion+0x86/0x160
> [427468.298375] __flush_workqueue+0x152/0x420
> [427468.298392] nfsd4_destroy_session+0x1b6/0x250 [nfsd]
> [427468.298456] nfsd4_proc_compound+0x34c/0x660 [nfsd]
> [427468.298515] nfsd_dispatch+0x1a1/0x2b0 [nfsd]
> [427468.298568] svc_process_common+0x295/0x610 [sunrpc]
> [427468.298643] ? svc_recv+0x491/0x810 [sunrpc]
> [427468.298711] ? nfsd_svc+0x370/0x370 [nfsd]
> [427468.298776] ? nfsd_shutdown_threads+0x90/0x90 [nfsd]
> [427468.298825] svc_process+0xad/0x100 [sunrpc]
> [427468.298896] nfsd+0x99/0x140 [nfsd]
> [427468.298946] kthread+0xda/0x100
> [427468.298954] ? kthread_complete_and_exit+0x20/0x20
> [427468.298963] ret_from_fork+0x22/0x30
There aren't a lot of 6.1-era changes in either of these, but there
are some interesting behavior updates around session create replay
from early this year. I wonder if the 6.1 server is mishandling an
nfserr_jukebox situation in nfsd4_session_create.
Was the client actually attempting to mount or unmount?
Tom.
Thank by advance,
Best regards
Le mercredi 23 octobre 2024 à 19:38 +0000, Chuck Lever III a écrit :
On Oct 23, 2024, at 3:27 PM, Benoît Gschwind
<benoit.gschwind@xxxxxxxxxxxxxxxxx> wrote:
Hello,
I have a nfs server using debian 11 (Linux hostname 6.1.0-25-amd64
#1
SMP PREEMPT_DYNAMIC Debian 6.1.106-3 (2024-08-26) x86_64 GNU/Linux)
In some heavy workload some nfsd goes in D state and seems to never
leave this state. I did a python script to monitor how long a
process
stay in particular state and I use it to monitor nfsd state. I get
the
following result :
[...]
178056 I (idle) 0:25:24.475 [nfsd]
178057 I (idle) 0:25:24.475 [nfsd]
178058 I (idle) 0:25:24.475 [nfsd]
178059 I (idle) 0:25:24.475 [nfsd]
178060 I (idle) 0:25:24.475 [nfsd]
178061 I (idle) 0:25:24.475 [nfsd]
178062 I (idle) 0:24:15.638 [nfsd]
178063 I (idle) 0:24:13.488 [nfsd]
178064 I (idle) 0:24:13.488 [nfsd]
178065 I (idle) 0:00:00.000 [nfsd]
178066 I (idle) 0:00:00.000 [nfsd]
178067 I (idle) 0:00:00.000 [nfsd]
178068 I (idle) 0:00:00.000 [nfsd]
178069 S (sleeping) 0:00:02.147 [nfsd]
178070 S (sleeping) 0:00:02.147 [nfsd]
178071 S (sleeping) 0:00:02.147 [nfsd]
178072 S (sleeping) 0:00:02.147 [nfsd]
178073 S (sleeping) 0:00:02.147 [nfsd]
178074 D (disk sleep) 1:29:25.809 [nfsd]
178075 S (sleeping) 0:00:02.147 [nfsd]
178076 S (sleeping) 0:00:02.147 [nfsd]
178077 S (sleeping) 0:00:02.147 [nfsd]
178078 S (sleeping) 0:00:02.147 [nfsd]
178079 S (sleeping) 0:00:02.147 [nfsd]
178080 D (disk sleep) 1:29:25.809 [nfsd]
178081 D (disk sleep) 1:29:25.809 [nfsd]
178082 D (disk sleep) 0:28:04.444 [nfsd]
All process not shown are in idle state. Columns are the following:
PID, state, state name, amoung of time the state did not changed
and
the process was not interrupted, and /proc/PID/status Name entry.
As you can read some nfsd process are in disk sleep state since
more
than 1 hour, but looking at the disk activity, there is almost no
I/O.
I tried to restart nfs-server but I get the following error from
the
kernel:
oct. 23 11:59:49 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:49 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:49 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:49 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:49 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:59 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:59 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:59 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:59 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 11:59:59 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 12:00:09 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 12:00:09 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 12:00:09 hostname kernel: rpc-srv/tcp: nfsd: got error -104
when sending 20 bytes - shutting down socket
oct. 23 12:00:10 hostname kernel: rpc-srv/tcp: nfsd: got error -32
when sending 20 bytes - shutting down socket
oct. 23 12:00:10 hostname kernel: rpc-srv/tcp: nfsd: got error -32
when sending 20 bytes - shutting down socket
The only way to recover seems to reboot the kernel. I guess because
the
kernel force the reboot after a given timeout.
My setup involve in order :
- scsi driver
- mdraid on top of scsi (raid6)
- btrfs ontop of mdraid
- nfsd ontop of btrfs
The setup is not very fast as expected, but it seems that in some
situation nfsd never leave the disk sleep state. the exports
options
are: gss/krb5i(rw,sync,no_wdelay,no_subtree_check,fsid=XXXXX). The
situation is not commun but it's always happen at some point. For
instance in the case I report here, my server booted the 2024-10-01
and
was stuck about the 2024-10-23. I did reduced by a large amount the
frequency of issue by using no_wdelay (I did thought that I did
solved
the issue when I started to use this option).
My guess is hadware bug, scsi bug, btrfs bug or nfsd bug ?
Any clue on this topic or any advice is wellcome.
Generate stack traces for each process on the system
using "sudo echo t > /proc/sysrq-trigger" and then
examine the output in the system journal. Note the
stack contents for the processes that look stuck.
--
Chuck Lever
