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IZ73849: SYSTEM ASSERTS IN NFS_ASYNC_READDIR DUE TO ACCESSING FREED RNODE APPLIES TO AIX 5300-08

A fix is available

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APAR status

  • Closed as program error.

Error description

  • System asserts in nfs_async_readdir() with following
    stack:
    
    [04C0D654]nfs_async_readdir+000054 (F100068004DF2000,
    F10006800131CE80,
       F10006001A51C87C, 0000000004D6FFA8 [??])
    [04C14DC0]nfs3_readdir+000660 (??, ??, ??, ??)
    [04B50F08]aix2onc_readdir_eofp+0000A8 (??, ??, ??, ??)
    [004B7EEC]vnop_readdir+00008C (??, ??, ??)
    [005B4770]getdirent64+000170 (??, ??, ??)
    [00003844].svc_instr+000144 ()
    
    Problem typically seen on systems running with high
    number of biod threads
    

Local fix

  • Lower the number of biod threads to 4. Filesystem needs
    to be mounted
    with the new biods option.
    
    mount -o biods=4 <server_name>:<FS_NAME> <mount_point>
    

Problem summary

  • system asserts in nfs_async_readdir() with following
    stack:
    
     04C0D654 nfs_async_readdir+000054 (F100068004DF2000,
    F10006800131CE80,
    F10006001A51C87C, 0000000004D6FFA8  ?? )
     04C14DC0 nfs3_readdir+000660 (??, ??, ??, ??)
     04B50F08 aix2onc_readdir_eofp+0000A8 (??, ??, ??, ??)
     004B7EEC vnop_readdir+00008C (??, ??, ??)
     005B4770 getdirent64+000170 (??, ??, ??)
     00003844 .svc_instr+000144 ()
    
    Problem typically seen on systems running with high
    number of biod threads becase of a race condition in
    nfs code.
    

Problem conclusion

  • NFS client code is modified to take a hold on the vnode,
    before doing the async operation to avoid the race condition.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ73849

  • Reported component name

    AIX 5.3

  • Reported component ID

    5765G0300

  • Reported release

    530

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2010-03-31

  • Closed date

    2010-03-31

  • Last modified date

    2013-03-29

  • APAR is sysrouted FROM one or more of the following:

    IZ54301

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    AIX 5.3

  • Fixed component ID

    5765G0300

Applicable component levels

  • R530 PSY U832253

       UP10/05/17 I 1000

PTF to Fileset Mapping

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Document Information

Modified date:
29 March 2013