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processes stuck in D state

DISCUSSION Zeev Fisher 4 participants 5 messages May 5, 2003

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#0 lore raw

Hi!

I got a continuos problem of unkillable processes stuck in D state ( uninterruptable sleep ) on my Linux servers.
It happens randomly every time on other server on another process ( all the servers are configured the same with 2.4.18-10 kernel ). Here's an example :

root@lnx35 /]# ps -el|grep D

F S   UID   PID  PPID  C PRI  NI ADDR    SZ WCHAN  TTY          TIME CMD
000 D   911 29327     1  0  75   0    -  9382 lock_p ?        00:00:00 calibre
000 D   894 30049 15854  0  75   0    -  8995 lock_p ?        00:00:01 calibrewb
000 D   894 30092  8661  0  75   0    -  8995 lock_p ?        00:00:01 calibrewb
000 D   894 29773 26052  0  75   0    -  8977 lock_p ?        00:00:01 calibrewb

It was probably stuck while trying to get a lock (which was certainly free) on an NFS volume mounted from a Netapp server.

Enabling debug mode on rpc ( echo '65535' >/proc/sys/sunrpc/rpc_debug ) didn't gave me any clue. Tracing the stucked process pid doesn't give any output.

Those processes are there already few days and will stay there until next reboot.

The load average is now 4 ( although the machine is 100% idle ) and the system seems to work fine. If other programs are started again they run and use the same mounts that the processes above are stuck on.

Another detail is that those problems started when i added the 'intr' option to my nfs mounted fs but i'm not sure. Also, i can't easily check that since this problem is not reproducible.

Has anyone noticed the same behavior ? Is this a well known problem ?

Thanks for your help.

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Zeev Fisher - Unix System Administrator
Marvell Semiconductor Israel Ltd
Moshav Manof, D.N. Misgav 20184, ISRAEL
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#1 lore raw

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Quoted 1 line · Zeev Fisher

Hi!

Hi Zeev!

Quoted 5 lines

I got a continuos problem of unkillable processes stuck in D state ( uninterruptable sleep ) on my Linux servers.
It happens randomly every time on other server on another process ( all the servers are configured the same with 2.4.18-10 kernel ). Here's an example :

[snip]

Quoted 1 line

Has anyone noticed the same behavior ? Is this a well known problem ?

I've had the same problem with some 2.4.21-preX twice (or maybe more times, don't remember) on one of my machines.
IMHO it has something to do with NFS. (I'm using this box as a NFS-client). I wish, I could reproduce it one more time, to do some traces, etc on it. But I've not found a way to reproduce it, yet.

- --
Regards Michael Büsch
http://www.8ung.at/tuxsoft
16:50:44 up 52 min, 1 user, load average: 1.00, 1.00, 0.94
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#2 lore raw
Quoted 13 lines · Michael Buesch

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Quoted 1 line · Zeev Fisher

Hi!

Hi Zeev!

Quoted 5 lines

I got a continuos problem of unkillable processes stuck in D state ( uninterruptable sleep ) on my Linux servers.
It happens randomly every time on other server on another process ( all the servers are configured the same with 2.4.18-10 kernel ). Here's an example :

Quoted 9 lines

[snip]

Quoted 1 line

Has anyone noticed the same behavior ? Is this a well known problem ?

I've had the same problem with some 2.4.21-preX twice (or maybe more times, don't remember) on one of my machines.
IMHO it has something to do with NFS. (I'm using this box as a NFS-client). I wish, I could reproduce it one more time, to do some traces, etc on it. But I've not found a way to reproduce it, yet.

This happens when you mount an NFS mount with the 'hard' option (default) and a mount's handle expires incorrectly (eg: server crash). Read the mount manpage for an explanation to the downsides of using the 'soft' option.

Mike Waychison

Quoted 18 lines

- --
Regards Michael B�sch
http://www.8ung.at/tuxsoft
16:50:44 up 52 min, 1 user, load average: 1.00, 1.00, 0.94
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#3 lore raw

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Quoted 22 lines · Mike Waychison
Quoted 13 lines · Michael Buesch
Quoted 1 line · Zeev Fisher

Hi!

Hi Zeev!

Quoted 5 lines

I got a continuos problem of unkillable processes stuck in D state ( uninterruptable sleep ) on my Linux servers.
It happens randomly every time on other server on another process ( all the servers are configured the same with 2.4.18-10 kernel ). Here's an example :

[snip]

Quoted 7 lines
Quoted 1 line

Has anyone noticed the same behavior ? Is this a well known problem ?

I've had the same problem with some 2.4.21-preX twice (or maybe more times, don't remember) on one of my machines.
IMHO it has something to do with NFS. (I'm using this box as a NFS-client). I wish, I could reproduce it one more time, to do some traces, etc on it. But I've not found a way to reproduce it, yet.

Quoted 7 lines

This happens when you mount an NFS mount with the 'hard' option (default) and a mount's handle expires incorrectly (eg: server crash). Read the mount manpage for an explanation to the downsides of using the 'soft' option.

Mike Waychison

my fstab-entry:
192.168.0.50:/mnt/nfs_1 /mnt/nfs_1 nfs rw,hard,intr,user,nodev,nosuid,exec 0 0

from man mount:
[snip] The process cannot be interrupted or killed unless you also specify intr. [/snip]

I can't interrupt any process that accessed the NFS-server while shutting down the server, although intr is specified. _That's_ my problem. :)

- --
Regards Michael Büsch
http://www.8ung.at/tuxsoft
18:23:58 up 48 min, 3 users, load average: 1.20, 1.05, 0.93
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#4 lore raw
Quoted 37 lines · Michael Buesch

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Quoted 22 lines · Mike Waychison
Quoted 13 lines · Michael Buesch
Quoted 1 line · Zeev Fisher

Hi!

Hi Zeev!

Quoted 5 lines

I got a continuos problem of unkillable processes stuck in D state ( uninterruptable sleep ) on my Linux servers.
It happens randomly every time on other server on another process ( all the servers are configured the same with 2.4.18-10 kernel ). Here's an example :

[snip]

Quoted 7 lines
Quoted 1 line

Has anyone noticed the same behavior ? Is this a well known problem ?

I've had the same problem with some 2.4.21-preX twice (or maybe more times, don't remember) on one of my machines.
IMHO it has something to do with NFS. (I'm using this box as a NFS-client). I wish, I could reproduce it one more time, to do some traces, etc on it. But I've not found a way to reproduce it, yet.

Quoted 7 lines

This happens when you mount an NFS mount with the 'hard' option (default) and a mount's handle expires incorrectly (eg: server crash). Read the mount manpage for an explanation to the downsides of using the 'soft' option.

Mike Waychison

my fstab-entry:
192.168.0.50:/mnt/nfs_1 /mnt/nfs_1 nfs rw,hard,intr,user,nodev,nosuid,exec 0 0

Quoted 6 lines

from man mount:
[snip] The process cannot be interrupted or killed unless you also specify intr. [/snip]

I can't interrupt any process that accessed the NFS-server while shutting down the server, although intr is specified. _That's_ my problem. :)

I had a similar problem with SuSE's 2.4.18. Random processes seemed to go into D state from whence intr is useless.

I rebuilt the kernel with NFSv3 disabled and that problem went away. The logs are full of

    May  5 14:54:15 duncan kernel: NFS: NFSv3 not supported.
    May  5 14:54:15 duncan kernel: nfs warning: mount version older than kernel

but that i can live with. Processes hung and umount failing i cannot abide.

If there is a better answer, i'm listening.

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