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IZ70019: POSIX AIO DEADLOCK IF USER PROCESS SETPRI BETWEEN AIO OPERATIONS APPLIES TO AIX 5300-08

A fix is available

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APAR status

  • Closed as program error.

Error description

  • AIO deadlock when the user code changes priority (setpri)
    on the user process while the aio threads are working.
    This is a rare timing issue.
    The hang can look something like
    
    (12)> f 195
        pvthread+006180 STACK:
        [002ADE8C]slock_ppc+00043C (0054079C, 00001080 [??])
        [00009554].simple_lock+000054 ()
        [02BD5248]suspend_it+000060 (??, ??, ??, ??, ??, ??)
        [02BD53DC]suspend_set+0000C4 (??, ??, ??, ??, ??, ??,
    ??)
        [02BD0D5C]posix_iosuspend_common+0000E8 (??, ??, ??,
    ??)
        [02BCFF80]_posix_iosuspend+000190 (??, ??, ??)
        [00003B3C].sys_call+000000 ()
        [kdb_get_memory] no real storage @ 314838A8
    

Local fix

  • Issue setpri for the all processes before issuing any
    AIO operations.
    

Problem summary

  • Threads can hang,  if the priority of it is changed while aio
    request is in progress with following stack trace
    
     002ADE8C slock_ppc+00043C (0054079C, 00001080  ?? )
     00009554 .simple_lock+000054 ()
     02BD5248 posix_aio.ext:suspend_it+000060 (??, ??, ??, ??, ??,
    ??)  02BD53DC posix_aio.ext:suspend_set+0000C4 (??, ??, ??, ??,
    ??, ??, ??)
     02BD0D5C posix_aio.ext:posix_iosuspend_common+0000E8 (??, ??,
    ??, ??)  02BCFF80 posix_aio.ext:_posix_iosuspend+000190 (??,
    ??, ??)  00003B3C .sys_call+000000 ()
    

Problem conclusion

  • keep record of the locks acquired
    

Temporary fix

Comments

APAR Information

  • APAR number

    IZ70019

  • Reported component name

    AIX 5.3

  • Reported component ID

    5765G0300

  • Reported release

    530

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2010-02-09

  • Closed date

    2010-02-09

  • Last modified date

    2013-03-29

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

    IZ66336

  • 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 U832219

       UP10/03/23 I 1000

PTF to Fileset Mapping

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Document Information

Modified date:
29 March 2013