IC90730: DEADLOCK BETWEEN CDRACCEPT THREAD AND GCREQ THREAD INVOLVING THE PERMNIFG MUTEX AND CDR_GC CONDITION

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APAR status

  • Closed as program error.

Error description

  • Some server ER threads get deadlocked, and it prevents the
    server from responding and processing any further cdr commands.
    
    The deadlock looks like the following:
    
    You'll see 1 or more threads waiting on the permNIFG mutex
    (onstat -g lmx output):
    
    Locked mutexes:
    mid      addr     name               holder   lkcnt  waiter
    waittime
    3289     49e55708 permNIFG           -1       0      3637
    10782
    
    8301     8325
    
    12489    5841
    
    15774    3904
    
    19893    1447
    
    *NOTE holder of -1 indicates the mutex has been share locked
    rather then exclusively locked...multiple threads could get a
    share lock on a mutex at a time, thus there is no 1 thread id
    owner, so -1 is used as the thread id of the owner when share
    locked*
    
    So this shows that the permNIFG mutex is share locked...one of
    it's waiters, thread id 3637 is a GCReq thread.  That thread has
    the following stack trace:
    
    mt_lock_wait
    mt_lock
    nifiExternProtect
    nifUnblockNifSendThreads
    dac_start_stop_replset
    gsi_start_replset
    clientRequestThread
    cdrTrampolineThread
    startup
    
    In clientRequestThread() this GCReq thread places a lock on the
    global catalog which is what activates people to start waiting
    on the CDR_GC condition.
    
    So now, the thread that has the share lock on the permNIFG mutex
    appears to be waiting on the CDR_GC condition (from onstat -g
    ath and it's stack trace):
    
    Threads:
     tid     tcb      rstcb    prty status                vp-class
    name
     4083    506d1018 49e1ac84 1    cond wait  CDR_GC       1cpu
    cdraccept
    
    stack:
    yield_processor_svp
    mt_wait
    gcLock
    nifiAccept
    nifGenericAccept
    cdraccept
    spawn_thread
    startup
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users                                                    *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Update to IDS-11.70.xC8                                      *
    ****************************************************************
    

Problem conclusion

  • Problem Fixed In IDS-11.70.xC8
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC90730

  • Reported component name

    INFORMIX SERVER

  • Reported component ID

    5725A3900

  • Reported release

    B70

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-03-08

  • Closed date

    2014-02-26

  • Last modified date

    2014-02-26

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

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

Fix information

  • Fixed component name

    INFORMIX SERVER

  • Fixed component ID

    5725A3900

Applicable component levels

  • RA10 PSN

       UP

  • RA10 PSY

       UP

  • RB10 PSN

       UP

  • RB10 PSY

       UP

  • RB50 PSN

       UP

  • RB50 PSY

       UP

  • RB70 PSN

       UP

  • RB70 PSY

       UP

  • RC10 PSN

       UP

  • RC10 PSY

       UP



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Document information


More support for:

Informix Servers

Software version:

B70

Reference #:

IC90730

Modified date:

2014-02-26

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