Bug 670734

Summary: kernel panic at __rpc_create_common() when mounting nfs
Product: Red Hat Enterprise Linux 6 Reporter: Takashi Sato <tsato>
Component: kernelAssignee: Takashi Sato <tsato>
Status: CLOSED ERRATA QA Contact: Petr Beňas <pbenas>
Severity: medium Docs Contact:
Priority: low    
Version: 6.0CC: bfields, dhowells, jiali, jlayton, kzhang, pbenas, pstehlik, rwheeler, steved
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: kernel-2.6.32-112.el6 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-05-23 20:37:59 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Attachments:
Description Flags
patch for linux-2.6.32-71.el6.x86_64 none

Description Takashi Sato 2011-01-19 06:46:07 UTC 
Created attachment 474201 [details]
patch for linux-2.6.32-71.el6.x86_64

Description of problem:

When mounting NFSv4 filesystem, NFS client's kernel panic for a BUG_ON at
__rpc_create_common().

  The panic place is:
    rpc_mkpipe
      __rpc_lookup_create()          <=== find pipefile *idmap*
      __rpc_mkpipe()                 <=== pipefile is *idmap*
        __rpc_create_common()
          ******  BUG_ON(!d_unhashed(dentry)); ******    *panic*

Version-Release number of selected component (if applicable):

Red Hat Enterprise Linux 6.0
kernel-2.6.32-71

How reproducible:
# cat /etc/exports
/nfsv4        *(rw,insecure,no_root_squash,fsid=0)

# mkdir -p /nfsv4

# service nfs restart

# cat mount-panic.sh
#!/bin/sh
LOOPTOTAL=768
LOOPCOUNT=0
while [ $LOOPCOUNT -ne $LOOPTOTAL ]
do
        ((LOOPCOUNT += 1))
        service nfs restart
        /usr/sbin/rpc.idmapd
        mount -t nfs4 127.0.0.1:/ /mnt || return;
        ls -l /var/lib/nfs/rpc_pipefs/nfs/*
        umount /mnt;
        echo $LOOPCOUNT
done

# sh mount-panic.sh

Actual results:
Panic happens while the above script is running.

Expected results:
The script completes.

Additional info:
It's reported on the linux-nfs community, too.
http://marc.info/?l=linux-nfs&m=129231689022990&w=2

Patch for linux-2.6.32-71.el6.x86_64 is attached.
Comment 3 RHEL Program Management 2011-01-19 14:50:41 UTC 
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.
Comment 4 Aristeu Rozanski 2011-02-03 16:20:04 UTC 
Patch(es) available on kernel-2.6.32-112.el6
Comment 8 Petr Beňas 2011-02-15 13:27:31 UTC 
Reproduced in 2.6.32-94.el6 and verified in 2.6.32-104.el6.
Comment 9 errata-xmlrpc 2011-05-23 20:37:59 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0542.html