Bug 746162 - Diskless system hangs when using NFSv4 with system authentication
Summary: Diskless system hangs when using NFSv4 with system authentication
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.1
Hardware: x86_64
OS: All
unspecified
medium
Target Milestone: rc
: ---
Assignee: Red Hat Kernel Manager
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-10-14 07:21 UTC by Ondrej Valousek
Modified: 2013-03-13 17:18 UTC (History)
6 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-10-18 13:00:39 UTC
Target Upstream Version:

Attachments (Terms of Use)
/var/log/messages from a diskless system running RHEL-6 (785.71 KB, text/plain)
2011-10-14 07:21 UTC, Ondrej Valousek 		no flags Details
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Description Ondrej Valousek 2011-10-14 07:21:27 UTC 
Created attachment 528160 [details]
/var/log/messages from a diskless system running RHEL-6

System hangs when (processes stuck in the D state) a diskless system booting from a NFS server uses NFSv4.
A SysRQ traces and the kernel log is attached.

The problem is easily reproducible.
Comment 2 Ondrej Valousek 2011-10-14 07:48:02 UTC 
Note that the "adclient" process that you see stuck in the D state is getting
user/group attributes (UIDs/GIDs) from Active Directory.
I guess there must be some dead loop here as well where rpc.idmapd is asking
for user's name and hence it uses (indirectly, via the NSS library) adclient to
complete the job.

I am looking for some ideas on how to avoid this situation.

Ondrej
Comment 3 J. Bruce Fields 2011-10-14 21:37:58 UTC 
Does adclient need to access nfs?  If so, then no, this isn't going to work....
Comment 4 Ondrej Valousek 2011-10-18 07:41:28 UTC 
Did some more investigation and it turned out that adclient uses /var/centrifydc directory which _was_ mounted via NFSv4.
The problem seems to vanish (I can not replicate) if I mount the directory via NFSv3 - which makes a sense actually.

Sorry for wasting your time here - please close this call.
Thanks,

Ondrej
Comment 5 J. Bruce Fields 2011-10-18 13:00:39 UTC 
(In reply to comment #4)
> Did some more investigation and it turned out that adclient uses
> /var/centrifydc directory which _was_ mounted via NFSv4.
> The problem seems to vanish (I can not replicate) if I mount the directory via
> NFSv3 - which makes a sense actually.

Yes, that's as expected; thanks for the confirmation.
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